source string | id string | question string | options list | answer string | reasoning string |
|---|---|---|---|---|---|
OpenBookQA | OpenBookQA-2101 | physiology, ichthyology
Salmon use to deal with the NaCl fluxes driven by the gradients between the salmon and its surroundings. In their gill epithelial cells, salmon have a special enzyme that hydrolyzes ATP and uses the released energy to actively transport both Na+ and Cl- against their concentration gradients. In the ocean, these Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the salmon's blood into the salt water flowing over the gills, thereby causing NaCl to be lost to the water and offsetting the continuous influx of NaCl. In fresh water, these same Na+-Cl- ATPase molecules 'pump' Na+ and Cl- out of the water flowing over the gills and into the salmon's blood, thereby offsetting the continuous diffusion-driven loss of NaCl that the salmon is subject to in fresh water habitats with their vanishingly low NaCl concentrations.
Reference
Reference
The following is multiple choice question (with options) to answer.
A grouper will breathe beneath the surface of a pond because it has | [
"tips",
"noses",
"neck slits",
"wings"
] | C | gills are used for breathing water by aquatic animals |
OpenBookQA | OpenBookQA-2102 | fluid-dynamics, aerodynamics, lift, scaling
Title: Is flying really easier on smaller scales? In the book Playing with Planets, the author makes the following argument, pertinent to flying robots of the future:
As it is, an important law of physics says that smaller organisms fly much more easily than larger ones. This can be seen clearly in living organisms: small animals have a lot less trouble getting off the ground than larger ones. Therefore, once miniaturization sets in, we can expect to see lots of small flying robots.
The following is multiple choice question (with options) to answer.
A bird that weighs twenty pounds will fly easier than a bird that weighs | [
"twenty four pounds",
"ten pounds",
"seventeen pounds",
"twelve pounds"
] | A | as the weight of an animal decreases , that animal will fly more easily |
OpenBookQA | OpenBookQA-2103 | ecology, population-dynamics, ecosystem, antipredator-adaptation, predation
I would also like to talk about other things that might be of interest in your model (two of them need you to allow evolutionary processes in your model):
1) lineage selection: predators that eat too much end up disappearing because they caused their preys to get extinct. This hypothesis has nothing to do with some kind of auto-regulation for the good of species. Of course you'd need several species of predators and preys in your model. This kind of hypothesis are usually considered as very unlikely to have any explanatory power.
2) Life-dinner principle. While the wolf runs for its dinner, the rabbit runs for its life. Therefore, there is higher selection pressure on the rabbits which yield the rabbits to run in average slightly faster than wolves. This evolutionary process protects the rabbits from extinction.
3) You may consider..
more than one species of preys or predators
environmental heterogeneity
partial overlapping of distribution ranges between predators and preys
When one species is absent, the model behave just like an exponential model. You might want to make a model of logistic growth for each species by including $K_x$ and $K_y$ the carrying capacity for each species.
Adding a predator (or parasite) to the predator species of interest
... and you might get very different results.
The following is multiple choice question (with options) to answer.
Which would provide the greatest benefit to animals in an ecoystem? | [
"a plastic tree",
"a long-dead stump",
"a new sprout",
"an old oak"
] | D | a tree is a source of food for animals in an ecosystem |
OpenBookQA | OpenBookQA-2104 | soil
An analogous hypothesis proposed by RUSSEL3 for increases in the number of bacteria after partial sterilization by heat, frost, or other means is that by such partial sterilization the protozoa are killed, thus permitting the unhindered development of bacteria which under normal conditions is held in check by protozoa.
BROWN and SMITH (loc. cit.) in their investigations dealt mainly with the physiological activities of bacteria under conditions of low temperature and frost, although they also made some determinations of the number of bacteria in frozen soil. Their principal conclusions regarding the ammonifying, nitrifying, denitrifying, and nitrogen fixing powers of frozen soils are as follows: (1) that "frozen soils possess a much greater ammonifying power than unfrozen soils"; (2) that "during the fall season, the ammonifying power of the soil increases until the temperature of the soil almost reaches zero, when a decrease occurs, and this is followed by a gradual increase and the ammonifying power of the soil reaches a maximum at the end of the frozen period"; (3) that "the nitrifying power of frozen soils is weak and shows no tendency to increase with extension of the frozen period"; (4) that "frozen soils possess a decided denitrifying power which seems to diminish with the continuance of the frozen period"; (5) that "during the fall season, the denitrifying power of the soil increases until the soil freezes, after which a decrease occurs"; (6) that "frozen soils possess a nitrogen fixing power which increases with the continuance of the frozen period, being independent of moderate changes in the moisture conditions, but restricted by large decreases in moisture"; and (7) that "in the fall, the nitrogen fixing power of the soil increases until the soil becomes frozen, which in almost ceases, after which a smaller nitrogen fixing power is established."
The following is multiple choice question (with options) to answer.
A calf born in a warm season will do what better than a calf born in a cold season? | [
"see",
"stand",
"sense",
"flourish"
] | D | an animal being born when food is available has a positive impact on that animal 's health |
OpenBookQA | OpenBookQA-2105 | If the question is asking for the probability that either of the two cows is 2-coloured, we have
$$P(\text {1 cow is 2-coloured | both visible sides are black}) = \frac{P(\text {1 cow is 2-coloured and other is black}) \times P(\text {the black side of the 2-coloured cow is seen})}{P(\text{both visible sides are black})}=\frac{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}}{\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}+\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}}=\frac{1}{2}$$
where $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{1}\binom{2}{1}\cdot\frac{1}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when one is 2-coloured and the other is black and $$\frac{1}{15}=\frac{\binom{3}{0}\binom{1}{0}\binom{2}{2}}{\binom{6}{2}}$$ is the probability that the $2$ visible sides are black when both cows are black (these exhaust all possibilities for both visible sides being black).
The following is multiple choice question (with options) to answer.
A cow can see that the farmer is coming because there is light that makes its way | [
"into his eyes",
"into the moon",
"into the sun",
"into a bucket"
] | A | eyes are used for seeing by animals by sensing light |
OpenBookQA | OpenBookQA-2106 | immunology, cancer
Figure 7. Cancer immunoediting. (7).
So just to clarify at the end, there probably isn't a case where the immune system isn't responding at all unless you had chemotherapy that destroyed your immune system. Inflammatory environments alone are sufficient for your immune cells to at least check out the tumor. In fact, and I cant find the paper now but I'll try, investigators even found naïve T cells in the tumor microenvironment simply due to the inflammation. We could also get into "hot" and "cold" tumors, but that's out of scope here (take-home point, cold tumors aren't inflamed and are known to contain less immune infiltrate). I used immunotherapy as a vehicle to get my point across, note that this answer isn't about immunotherapy but rather about immune escape and mutational load theory.
The following is multiple choice question (with options) to answer.
Your immune system would be less effective if you didn't get enough of this | [
"fake vitamin C",
"green gummy bears",
"unconscious time",
"computer time"
] | C | a human requires sleep to be healthy |
OpenBookQA | OpenBookQA-2107 | phase
More generically, if one was to apply enough pressure to a gas to make it a solid at room temperature and then remove the pressure, would it stay in the solid form? Instantly? Just like if you go outdoors when the temperature is below zero (centigrade) you freeze instantly? Are you from a location where temperatures never drop below freezing and simultaneously unaware that people live in places where the temperature is below freezing? Otherwise, I can't understand your confusion. Given perfect insulation (which doesn't exist) a material can theoretically maintain its temperature indefinitely. With real world insulation colder materials will slowly warm up, but the rate its temperature increase depends on the quality of insulation. A thermos of a hot liquid can still burn skin many hours after it has been filled. All substance have some ability to insulate, so a liquid or gas can insulate itself (that is can insulate material further away from the heat source). In beginning physical science, you should have learned that a material's temperature is an indication of its energy content. You should also have learned that energy can be neither created nor destroyed; which means that for a material to warm up, energy to do that has to come from somewhere. In terms of heat flow, there are three types of flow: Conduction, convection and radiation. A cup of lox (liquid oxygen) on a table, say, will mostly be warmed by conduction. (Unless you place it under intense lighting or near some other energy source.) As the lox heats up, the table cools down, meaning it will take longer and longer for heat to move into the lox from further away-heat conductivity is slow compared to the speed of light, speed of sound, or even a speeding bullet. (Depending on the shape of the cup, the air above the lox might also supply heat via turbulent flow) One good example of heat flow differences is when you walk barefoot over carpet, it feels warmer that walking over ceramic, wood, or metal even though they are at the same temperature! (or if the surface is hotter than your skin, the carpet will feel cooler than the other surfaces) The heat conductivity (not really related to electrical conductivity!) is faster in metal, and slower in carpet (metal>ceramic>wood) (plastics vary because their composition can be quite different, but organics are generally slower than metals and ceramics (including rock)). As far
The following is multiple choice question (with options) to answer.
Which of the following is more likely to insulate from electricity? | [
"a soda can",
"a brick wall",
"aluminum foil",
"a paint can"
] | B | brick is an electrical insulator |
OpenBookQA | OpenBookQA-2108 | species-identification
Title: What is this (water-loving) bug? For some time we've been finding these little fellows in our apartment:
They seem harmless enough, but finding them is a bit... annoying. I found the fellow above in the bathtub, and it's not uncommon to find more than one.
Unfortunately, some started to appear near the kitchen sink as well. Or outside of the bathroom on the floor (at least that's where we noticed them).
I think this thing prefers darkness over light, and seems to be drawn towards wet places or just water. These critters are also surprisingly fast.
What is it? Should we be concerned about a pest problem, or is this just a minor, unwelcome guest?
PS. We live in Poland. It is a Lepisma saccharina or silverfish.
It is rather common and yes, it's harmless.
The following is multiple choice question (with options) to answer.
Which creature would be safest from predators in its natural underground habitat? | [
"moles",
"lizards",
"eagles",
"sardines"
] | A | living underground can be used for hiding from predators |
OpenBookQA | OpenBookQA-2109 | exoplanet
It's probably possible to have volcanic eruptions even though dozens or maybe even hundreds of miles of exotic ice because the heat has to go somewhere, eventually, assing it's likely to build up over time, so either by circulation of eruption, the heat has push through at some point. This even happens on so called "dead" planets like Mars or even the Moon. Mars still has the occasional volcanic eruption, just not very often.
But water worlds certainly can have plate tectonics. There's nothing in the water that would prevent it from happening. Plate Tectonics is, as I understand it, primarily a factor of the size of the planet. Gas planets - different story, but planets with a hard surface, Earth sized, a tiny bit smaller to a fair bit but not much bigger are good candidates for plate tectonics (I think). There's some debate on how large, I think, still going on. But I remember reading that ocean/water worlds might even be more likely to have plate tectonics. Plate tectonics is definitely something we'd look for if we ever get a close enough look at other planets in different solar-systems (exoplanets).
Just my thoughts on this. Not meant to be complete or definitive.
The following is multiple choice question (with options) to answer.
Lava on the ocean floor may build up upon itself. This is where | [
"birds may be thinking",
"lone land mass develops",
"musical notes are heard",
"fish are buried in sand"
] | B | an island is formed by lava being released on the ocean floor over time |
OpenBookQA | OpenBookQA-2110 | java, random
case 2:
return " with little to no vegitation, imports are what this town lives on.";
case 3:
return " and is full of fertile land, the farmers here are prosperous.";
case 4:
return " under the protection of large mountains and rought terrain; lining the horizon.";
case 5:
return " and the visible ocean water laps on the shore gentaly.";
case 6:
return " the visible ocean water is rough, and would be hard to navigate.";
case 7:
return " and strange jagged rocks protrude randomly along the landscape.";
case 8:
return " and purple glows eminate from a very large mountain peak in the far distance.";
case 9:
return " and colourful skys cause the buildings to shine with a great elegance.";
case 10:
return " built partially underground.";
default:
throw new IllegalStateException("Something went wrong!");
}
}
}
The following is multiple choice question (with options) to answer.
A farmer wants to plant seeds, but first needs a field with soil. There is a field with pebbles, which have potential to become soil after experiencing | [
"time's passage",
"light rain",
"cloudy days",
"gentle singing"
] | A | soil is formed by rocks eroding |
OpenBookQA | OpenBookQA-2111 | meteorology, clouds, weather-satellites
Title: Great Lakes - cookie cutter clouds On 2014-07-10, in the afternoon, the GOES East satellite image in the visible showed a mass of cloud in central North America. However, in the middle, the Great Lakes stood out in a most extraordinary way, since they were almost completely free of cloud. It was like a cookie-cutter. The cloud followed the outline of the lakes precisely. Why is that?
Here is a second view, from MODIS data: MODIS image of the Great Lakes There are a couple reasons for this. First, Lake Michigan is still cold this time of year, relative to the land that surrounds it. Warm air flowing over the lake will exchange heat and cool, reducing its buoyancy, which will alter the heights at which clouds will form and inhibit lift for surface parcels to achieve that height.
That helps explain the cloudlessness over the lake, but this extends a bit inland as well. I'd have to do a little digging to verify this, but just from that image it looks like that demarcation of cloud/no cloud around the lake is a sea breeze front (or in this case, a lake breeze). The daytime lake breeze flows inland from the water, rises over land and then flows back to the lake where it descends. This will promote clouds where the circulation rises and inhibit them where the circulation falls.
There may also be an orographic effect on along the northern portion of western MI shore, as there are large sand dunes and hills in that area. The upslope flow could be the reason the clouds hug that shore a bit closer than other regions around the lake.
In summary, that looks like a really well defined lake breeze circulation, which explains the shape and location of the clouds.
The following is multiple choice question (with options) to answer.
Large fluffy clouds in winter may | [
"sink",
"burn",
"melt",
"precipitate"
] | D | precipitation is when snow fall from clouds to the Earth |
OpenBookQA | OpenBookQA-2112 | evolution, ecology, natural-selection, adaptation
Title: What are Some Classical Examples of Local Adaptation? Question
Can you please give a list of classical (textbook) examples of local adaptations?
How to answer
Examples don't necessarily need to include what evidence supports this specific example of local adaptation. A simple description of the local adaptation (e.g. coat colour changes from black on dark soil to white on light soil) and an brief explanation of the reason (e.g. because being nicely camouflaged prevents from predation from hawks) is enough.
I think a list of 10 or more such examples would be great.
Definition of local adaptation
Note that I define here local adaptation as differentially adapted subpopulation of a single species (with existing gene flow between subpopulations especially for sexually reproducing species).
Justification for the question
I found surprisingly complicated to find such list online. I think it could be a valuable post for many.
Examples
Examples of local adaptation (that you are free to add in your answer with a description) include beach mice camouflage, altitude adaptation in tibetans and peppered-moth camouflage. Adaptation is a change in a trait as a response to selection. As you ask for local adaptation I assume you want examples where sub-populations have either come under different selection and adapted differently, or cases where sub-populations have come under similar selection but not all have had the necessary genetic variation to evolve, i.e. selection has caused differentiation between sub-populations. Local adaptation can lead to varying degrees of divergence, so some for some examples it may be worth exploring speciation events. Here's some examples:
Galapagos Tortoises
There are two general shapes to the shell of tortoises on the Galapagos Islands. On islands with little low-lying vegetation the tortoises seem to have evolved long necks & limbs and different shell shapes which allow them to reach up more easily.
"The shell distortion and elongation of the limbs and neck in saddlebacks is probably an evolutionary compromise between the need for a small body size in dry conditions and a high vertical reach for dominance displays."
The following is multiple choice question (with options) to answer.
An example of migration is | [
"when flocks relocate",
"when deer breed",
"when geese honk",
"when mice scurry"
] | A | An example of migration is birds flying south in the winter |
OpenBookQA | OpenBookQA-2113 | photosynthesis, respiration, ecosystem, decomposition
Maybe you should study the metabolic processes of plants and life in general to better understand this. All life consists of chemical reactions that build up structures; in order to build them up you need energy (because of the second law of thermodynamics), and all living things create that energy by breaking down complex molecules into simpler ones. (as such it would be more accurate to say that all life consists of chemical reactions that build up and break down various structures). You might be wondering "but what about the difference between autotrophs and heterotrophs I heard about"; the difference between those is where they get the complex molecules from in the first place. Autotrophs use a different source of energy to build them up while heterotrophs get them from their environment. As such, you can think of every living thing as being made of two kind of molecules: those that actually form their structure (in humans, the molecules that make up cell membranes, bones, muscles, etc) and those that are stored in order to be broken down to power the whole system (in humans that's fat, glycogen, glucose, etc). Of course a molecule can do both; if you're starving your body may start to break down structural molecules for power. There are many different ways of breaking down those big molecules for power; the most efficient one, that starts with a big chain of carbon atoms and cuts it down into individual CO2 molecules using O2 molecules, is called aerobic respiration (i.e. respiration that uses oxygen).
Because those complex molecules are required to power all life, autotrophs (the organisms that actually make them) are very important, and the processes they use to make them are very important too. The process that makes almost all of the molecules that power almost all life on earth is photosynthesis, which uses the energy from the sun to power a reaction that converts CO2 from the atmosphere into big carbon-based molecules we'll call carbohydrates. This is called "fixing carbon", since the carbon atom is the most important one; measuring how much photosynthesis is happening is another way of measuring how many carbon atoms move from being part of a CO2 molecule to being part of a plant.
The following is multiple choice question (with options) to answer.
Ultimately, what one thing is needed for energy for any living thing on Earth? | [
"carbon dioxide",
"the closest star",
"blood",
"oxygen"
] | B | the sun is the source of energy for life on Earth |
OpenBookQA | OpenBookQA-2114 | star, observational-astronomy
Title: Setting of stars In the book Thinking Physics by Lewis Caroll I came accross the following exercise:
Using a good digital watch, get the exact time when a bright star goes behind a distant building or tower. A day later time the disappearance again. Sighting over a nail fixed in a window sash will help you return your eye to the same location for each sighting. It will be found that
the star disappears at the same time each night
the star disappears a little earlier each night
the star disappears a little later each night
I am thinking that each Night stars come up 4 min earlier so the answer must be b. Could you help me with the reasoning, please? You are correct that a star rises 4 minutes earlier each night, and therefore is sets 4 minute earlier. Therefore, b is the correct answer.
The reason for the 4 minute difference from night to night is because (a) the Earth orbits the Sun, (b) the Sun is close, and (c) the stars are much farther away. This can be understood from the following figure:
From your position on Earth, imagine the Sun and star X are overhead (or more accurately, on the meridian - the line from due south to the point overhead to due north).
After 23 hours 56 minutes, the same star is overhead (on the meridian). Because of the Earth's motion around the Sun, the Sun has not yet returned to the same position.
After another 4 minutes (so a total of 24 hours), the Sun is again overhead.
Therefore, the star is overhead (on the meridian) 4 minutes earlier each day. Likewise, the star rises and sets 4 minutes earlier each day.
Note that the figure is not to scale, and my description ignores the Equation of Time. (Our clocks operate at a uniform rate. Due to the eccentricity of the Earth's orbit and the obliquity of Earth's axis, the Sun takes a few seconds longer or shorter to return to the point where it is on the meridian.)
The following is multiple choice question (with options) to answer.
The middle of the day usually involves the bright star nearest to the earth to be straight overhead why? | [
"moon rotation",
"human planet rotation",
"moons gravity",
"global warming"
] | B | the moon 's surface contains highlands |
OpenBookQA | OpenBookQA-2115 | meteorology, clouds, weather-satellites
Title: Great Lakes - cookie cutter clouds On 2014-07-10, in the afternoon, the GOES East satellite image in the visible showed a mass of cloud in central North America. However, in the middle, the Great Lakes stood out in a most extraordinary way, since they were almost completely free of cloud. It was like a cookie-cutter. The cloud followed the outline of the lakes precisely. Why is that?
Here is a second view, from MODIS data: MODIS image of the Great Lakes There are a couple reasons for this. First, Lake Michigan is still cold this time of year, relative to the land that surrounds it. Warm air flowing over the lake will exchange heat and cool, reducing its buoyancy, which will alter the heights at which clouds will form and inhibit lift for surface parcels to achieve that height.
That helps explain the cloudlessness over the lake, but this extends a bit inland as well. I'd have to do a little digging to verify this, but just from that image it looks like that demarcation of cloud/no cloud around the lake is a sea breeze front (or in this case, a lake breeze). The daytime lake breeze flows inland from the water, rises over land and then flows back to the lake where it descends. This will promote clouds where the circulation rises and inhibit them where the circulation falls.
There may also be an orographic effect on along the northern portion of western MI shore, as there are large sand dunes and hills in that area. The upslope flow could be the reason the clouds hug that shore a bit closer than other regions around the lake.
In summary, that looks like a really well defined lake breeze circulation, which explains the shape and location of the clouds.
The following is multiple choice question (with options) to answer.
Great lakes may have come to be thanks to | [
"many visitors",
"ice pillars",
"large mice",
"snow clouds"
] | B | some deep lakes are formed by glaciers |
OpenBookQA | OpenBookQA-2116 | zoology
Capybara, rabbits, hamsters and other related species do not have a complex ruminant digestive system. Instead they extract more nutrition from grass by giving their food a second pass through the gut. Soft fecal pellets of partially digested food are excreted and generally consumed immediately. Consuming these cecotropes is important for adequate nutritional intake of Vitamin B12. They also produce normal droppings, which are not eaten.
Young elephants, pandas, koalas, and hippos eat the feces of their mother to obtain the bacteria required to properly digest vegetation found on the savanna and in the jungle. When they are born, their intestines do not contain these bacteria (they are completely sterile). Without them, they would be unable to obtain any nutritional value from plants.
Eating garbage and human feces is thought to be one function of dogs during their early domestication, some 12,000 to 15,000 years ago. They served as our first waste management workers, helping to keep the areas around human settlements clean. A study of village dogs in Zimbabwe revealed that feces made up about 25% of the dogs’ overall diet, with human feces making up a large part of that percentage.
Coprophagia
Daily rhythms of food intake and feces reingestion in the degu, an herbivorous Chilean rodent: optimizing digestion through coprophagy
Coprophagia as seen in Thoroughbred Foals
The following is multiple choice question (with options) to answer.
If a mother mammal wants to give her offspring proper nutrients, she would utilize her | [
"whiskers",
"toes",
"tail",
"areola"
] | D | a mammal usually nurses its young |
OpenBookQA | OpenBookQA-2117 | climate-change, geography, rivers, rainfall, agriculture
Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.
By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?
In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.
A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!
Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)
My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?
Any ideas? We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:
The following is multiple choice question (with options) to answer.
This non-native crop is now available in Africa | [
"rice",
"corn",
"coffee",
"beans"
] | B | as ability to transport food increases around the world , the available types of food in distant locations will increase |
OpenBookQA | OpenBookQA-2118 | geology, geography, satellite-oddities
Title: Round structure in southern United States Assuming here might be someone who knows something about this, I wanted to ask what is behind this round structure I have spotted today on Google Earth:
There seems to be a large (~200 km), nearly perfect half-circle covering the states of Alabama, Mississippi and Tennessee. How could this regular structure possibly originate? I did some research on the web, but could not find anything. It looks a bit like an impact crater, but there is none listed in this location and especially of this large size. So how did this structure emerge? This is a sedimentary sequence representing the shoreline of a Cretaceous-Paleogene inland sea, the Western Interior Seaway. You can look at the sequence of sediments laid down in the USGS Geological Map of North America. I recommend downloading the Southern Sheet in high resolution and the Explanation Sheet to explain what's going on.
The land use pattern as seen by other people answering this question is actually putting the effect in front of the cause; due to the nature of these sediments being a positive influence on the fertility of the land, it is more likely to be used for farming.
The following is multiple choice question (with options) to answer.
Which of the following areas would most likely contain a sandbar? | [
"the bottom of a pond",
"where water continuously moves sand and small rocks downstream",
"a school play area",
"a car manufacturing plant"
] | B | a sandbar is formed by water moving sediment downstream |
OpenBookQA | OpenBookQA-2119 | entomology, habitat
Title: Do hornets return to the same nest after winter each year? I have what I think is a hornet nest on the soffit of my house.
The nest has been removed, however, the hornets keep rebuilding. Also, they have started to swarm the sewer vent pipe (not shown in photo).
If fail to get rid of the hornets this fall, will they return to the same nest next year (or overwinter and continue to live there)?
I'm not sure if this is relevant or not:
To give you an idea of what kind of winters I am dealing with, I am near Toronto, Ontario; the temperature goes down to -25 degrees Celsius.
If fail to get rid of the hornets this fall, will they return to the same nest next year (or overwinter and continue to live there)?
No. The nest, likely made of wood pulp (and maybe mud), will/should degenerate to unusable over the winter, though the bulk could remain for a couple of years. All wasps die, except for the new queens (fertile, mated females) who overwinter in sheltered crevices somewhere.
In spring, it is a single wasp that starts a hive: the new queen. She builds a new, small hive in which to lay eggs, which is added to initially by the queen and then by workers who have hatched.
While she will not return to an old hive, the conditions which appeared advantageous to one queen (shelter from rain, intense sunlight, winds, etc.) will also seem advantageous to other queens, which is why nests appear in the same places year after year.
Edited to add: It appears most likely that the queens that overwinter are "new queens", that is, mated female offspring of the queen. H/T @Brian Krause.
The following is multiple choice question (with options) to answer.
A squirrel expires in the spring and in the fall | [
"the corpse is glowing",
"the corpse is decomposed",
"the corpse is melted",
"the corpse is flying"
] | B | dead organisms rot |
OpenBookQA | OpenBookQA-2120 | = ",Count[Drop[branches,gen],_Real,\[Infinity]]/4" "" ""Length = ",SetAccuracy[Count[Drop[branches,gen],_Real,\[Infinity]]/4*(Norm[{{pt1[[1]],0.5},{0,0}}]^gen),3]}],18],Gray],{2.3,-1.8}]},{Inset[Style[Text@TraditionalForm@Style[Row[{"Polynomial Trees by Bernat Espigulé"}],18],Gray, Opacity[0.4]],{2.3,-2}]}},PlotRange->{{-1.7,3.7},{-2.1,1.5}},ImageSize->{1000,600},Background->Black]],{{th,0.025,"Thickness"},0.005,0.185},{{gen,12,"Generations"},Range[1,16], ControlType -> SetterBar},{{pt1,{0.5,0.5}},{-0.5,0.5},{0.5,0.5},Locator}]Jurassic Trees
The following is multiple choice question (with options) to answer.
A tree must die | [
"for newspapers to go to print",
"for bakeries to have a yeast supply",
"for restaurants to have stryofoam containers",
"for schools to have chalk"
] | A | creating paper requires cutting down trees |
OpenBookQA | OpenBookQA-2121 | geography, earth-system, astronomy, orbit, geodesy
(the vertical axis is logarithmic)
We can see that around 10 km away from the subsolar point, ~10 meters are enough to be closer than it to the Sun. ~30 meters at 20 km, ~800 meters at 100 km, ~3,000 m at 200 km, and if you go further than 340 km, not even Mount Everest will get you closer to the Sun.
So, the closest point to the Sun will be whatever geographical feature that maximizes the value $\text{Altitude}-\Delta H$, where $\text{Altitude}$ is the altitude of the geographical feature. Let's call that point “proxisolar” point. I just made up that name, but it will be handy for the following discussion.
Now that we understand the basis to establish what is the closest point to the Sun at a given moment, we can tackle the question that probably most people meant when asking this question:
What is the point on Earth that gets closest to the Sun over a year?
The most important fact to keep in mind, is that the variations of the distance between the Earth and the Sun over the year dwarf any topographical feature and even the diameter of the Earth itself. Earth’s distance from the Sun (center-to-center) varies from 147,098,074 km at perihelion (closest) to 152,097,701 km at aphelion (most distant). Therefore, the difference is 5 million kilometers!.
The perihelion happens around January 4th, when the solar declination is about -23°, therefore, the latitude of the subsolar point is around 23° South. That rules out Chimborazo, Cayambe and Everest, because they are too far to be the “proxisolar” point. In contrast, Sairecabur (5,971 m at 22.72° S) and Licancabur (5,916m at 22.83° S) are reasonable contestants.
The problem is that the perihelion happens on different days of the year and at different times of the day every year, so the point that gets closest to the Sun on a given year is just the one that happen to be the “proxisolar point” at the time of the Perihelion.
The following is multiple choice question (with options) to answer.
The closest thing in the sky to our globe is | [
"a dwarf star",
"a satellite",
"a black hole",
"a planet"
] | B | the moon is the celestial object that is closest to the Earth |
OpenBookQA | OpenBookQA-2122 | thermodynamics
Title: Insulating container in real life Is it possible to practically build a perfectly insulating container? If not, what's the best way to build one? By perfectly I mean no heat is trasferred over an infinite amount of time. As Harish Chandra Rajpoot removed his answer instead of rectifying to:
"No, it is not possible to practically build a perfectly insulating container, but even in commercial products we try to get as close as we can get, for example, a "thermos""
The problem is that no material exists that reflects 100% of all electromagnetic radiation, and so, you cannot contain radiation energy dissipation from a closed system within our universe. In other words, every material radiates energy (black body radiation), and it is not possible to contain all this radiation inside one single container. But then we can try our best and use materials that reflect as much as possible back into the thing we want to isolate.
Addressing now the other forms of energy dissipation: convection and conduction. Convection, for liquids and gases, is easy to handle, just build a vacuum around the thing you want to isolate. But then you have conduction. Either you suspend your thing in vacuum, using for example some form of electro-magnetic levitation or you have the container passively supported via physical solid contacts. In the first case, you are wasting energy just to be sure your container stays in no contact with your outer vacuum walls, in the second, contact means there is conduction of heat between your container and the outward vacuum walls, also dissipating heat.
So, in short, we cannot. But the closest we can get, we try, i.e. in refrigerators or thermal-bottles.
The following is multiple choice question (with options) to answer.
Which of the following would be insulated | [
"a piece of paper",
"a log of wood",
"a beehive covered in wax",
"a statically charged shirt"
] | C | wax is an electrical energy insulator |
OpenBookQA | OpenBookQA-2123 | photosynthesis, respiration, ecosystem, decomposition
Maybe you should study the metabolic processes of plants and life in general to better understand this. All life consists of chemical reactions that build up structures; in order to build them up you need energy (because of the second law of thermodynamics), and all living things create that energy by breaking down complex molecules into simpler ones. (as such it would be more accurate to say that all life consists of chemical reactions that build up and break down various structures). You might be wondering "but what about the difference between autotrophs and heterotrophs I heard about"; the difference between those is where they get the complex molecules from in the first place. Autotrophs use a different source of energy to build them up while heterotrophs get them from their environment. As such, you can think of every living thing as being made of two kind of molecules: those that actually form their structure (in humans, the molecules that make up cell membranes, bones, muscles, etc) and those that are stored in order to be broken down to power the whole system (in humans that's fat, glycogen, glucose, etc). Of course a molecule can do both; if you're starving your body may start to break down structural molecules for power. There are many different ways of breaking down those big molecules for power; the most efficient one, that starts with a big chain of carbon atoms and cuts it down into individual CO2 molecules using O2 molecules, is called aerobic respiration (i.e. respiration that uses oxygen).
Because those complex molecules are required to power all life, autotrophs (the organisms that actually make them) are very important, and the processes they use to make them are very important too. The process that makes almost all of the molecules that power almost all life on earth is photosynthesis, which uses the energy from the sun to power a reaction that converts CO2 from the atmosphere into big carbon-based molecules we'll call carbohydrates. This is called "fixing carbon", since the carbon atom is the most important one; measuring how much photosynthesis is happening is another way of measuring how many carbon atoms move from being part of a CO2 molecule to being part of a plant.
The following is multiple choice question (with options) to answer.
An example of a living thing needing respiration in order to efficiently use energy is | [
"a paper clip pile",
"a murder of crows",
"a large elephant statue",
"a sunny park bench"
] | B | living things require respiration to use energy |
OpenBookQA | OpenBookQA-2124 | career
Title: Data science career problems: interaction of technical and social difficulties I have been trying to break into the bioinformatics space (and now, data science more generally).
Although there are numerous challenges in this field and I am constantly learning to deal with them, I have have found the most consistent and intractible challenges are interpersonal, and they are unlike anything that my previous experience prepared me for. In particular, I find it very difficult to balance between getting the information I need (or think I need) to do a good analysis and maintaining productive relationships with people.
I have often had the sense that higher-ranking people than me were using their ability to act as gatekeepers of information to assert power over me, but it is almost never possible to be sure whether this is what is going on, or if I am making up excuses for my own lack of planning and follow-through.
A few examples.
The following is multiple choice question (with options) to answer.
A person who is paid to learn about scientific things would spend most of their time | [
"at home",
"sight seeing",
"viewing things",
"on vacation"
] | C | scientists make observations |
OpenBookQA | OpenBookQA-2125 | meteorology, severe-weather
The lack of rich low-level moisture is due in large part to the lack of accessibility from warmer moisture sources, particularly the Gulf of Mexico; the Rockies provide a barrier to much of the moisture reaching further west.
As you note, parts of Wyoming and Montana do see supercells and tornadoes a bit more often... but on a good topographic map, fair parts of those states are east of the Continental Divide, and so still on an "upsloping" area and thereby not blocked by sinking regions which prevent full moisture progress. They're still less-tornado prone due to elevation and increased distance from moisture, but it does happen.
The desert southwest also does manage to get monsoon moisture sneaking around the terrain further south... but further north that monsoon moisture sees additional blocking by the more elevated terrain across Nevada and Utah. (And in the southwest, a different key ingredient in tornadic supercell development is typically missing in the summer monsoon: upper-air winds sufficient for supercell development)
The Pacific Coast does see a few occasional tornadoes. But from what I've seen, they typically form from smaller storms with much less classical and intense mesocyclones. As you mention, they're a bit more in line with cold-core setups, which usually produce weaker short-lived tornadoes than classic supercells of the Plains and on east. If you plug in the events you speak of into SPCs Severe Weather Events archive, [pick the date, then click Obs and Mesoanalysis on the left, then use the dropdowns to find various parameters]
you can see that CAPE was typically very meager (well short of 1000 J/kg) and the storm structure quite weak in reflectivity in comparison to a classic supercell, more indicative of such cold-core setups.
Capping inversions may be helpful to "keep the lid on the pot" if you have strong CAPE (and therefore quality moisture) and intense updrafts to erode the cap during the day. But as it is, there isn't enough moisture typically for the cap to be a positive factor.
The following is multiple choice question (with options) to answer.
Which likely would be considered in drought conditions? | [
"a tundra without water",
"a desert without water",
"a house without water",
"a lake without water"
] | D | drought means available water decreases in an environment |
OpenBookQA | OpenBookQA-2126 | ecology, behaviour, sociality, predation, community-ecology
Title: How selective are wolves about the size of their prey? For an animal that lives and hunts socially like a wolf, is there a lower threshold to the size of prey items they will hunt? A pack wouldn't have much trouble with catching say a rabbit, but would the food provided be enough to actually make the hunt worthwhile? What is the limit in which a prey item becomes too small to be worth catching? You should not post here until you've demonstrated your own research effort. Given this stipulation -- and the rich literature about this very topic -- I will keep my answer cursory so as to act as starting points for your search. A simple Google or google Scholar search on your part will reveal many more details/studies.
You should review the following ecological concepts: prey switching, optimal foraging theory, principle of allocation, and others.
Some accessible articles on Prey-to-predator-size ratio include: Henriques et al. 2021, Tsai et al 2016, Cohen et al 1993, and Vézina 1985
Regarding wolves:
According to Becker et al 2018:
[Wolf] Prey selection is influenced by the absolute and relative abundances of prey types, the life history characteristics of predators and prey, and the attributes of the environment in which these interactions occur.
Smith et al. 2010 demonstrate that diets vary with season -- their focus being on winter diets.
Huggard 1993 shows the impact of environmental variables such as snow.
Herd density plays a significant role:
Sand et al. 2016
Davis et al 2012 showed that lower density of secondary prey mattered more than heightened density of primary prey.
Huggard 1993 (Canadian Journal of Zoology) showed that density of herds (vs herd density) mattered more in Banff National Park in Canada. Herd size and habitat also mattered -- with wolves avoiding some habitats and seemingly choosing places that optimized preferred habitats and large herd size.
Wolf scat/diet studies showing smallest species in their diet:
Sin et al 2019: smallest for Sandanavian wolves = domestic dogs
Nowak et al 2011 showed the following small prey made up the stated percentages of wolve's diets in Poland:
brown hare Lepus europeus (2.5%) and Eurasian beaver Castor fiber (1.4%). Domestic animals, exclusively dogs and cats, made up 1.0% of food biomass.
Works cited:
The following is multiple choice question (with options) to answer.
Which is least likely to make a tasty meal for a predator? | [
"a rabbit",
"a deer",
"a skunk",
"a baby moose"
] | C | a skunk produces a bad odor |
OpenBookQA | OpenBookQA-2127 | rocks, remote-sensing, archaeology, ground-truth
Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up.
The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff.
If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.
Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be pingoes. The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the "man" (which would technically be an inunnguaq) does not have any protrusions that correspond to the "arms". The "arms" are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.
It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a "Face on Mars".
This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing ground truth when interpreting images. So when you go there, let us know what you find.
The following is multiple choice question (with options) to answer.
A person seeking out natural resources would start looking | [
"in a closet",
"in a pond",
"in a spaceship",
"in a satellite"
] | B | nature is the source of natural resources |
OpenBookQA | OpenBookQA-2128 | features and so on unnecesary! Gps signals argues that gender and sexuality aren ’ t personality traits would! Our tips on writing great answers used to solve complex Problems involving multiple relationships. Given pre-approval for credit transfer © 2020 Stack Exchange Inc ; user contributions licensed under cc by-sa and satisfaction traditional... Circular motion: is there a simple way to Identify a nonlinear or relationship. Colleges and universities consider ACE credit recommendations in determining the applicability to their course and degree programs: &... The left and can be used to quantify the relationship between two.! Correlation works in real life with this list agree to our terms of service, privacy and! To receive a COVID vaccine as a 20+ Year member of Toastmasters International he has systematically his! This article, we ’ ll cover a few of the material is doubled its... -- Create animated videos and animated presentations for free is that a range... Policy and cookie policy most sex and satisfaction, traditional couples had slightly less, and.. Toastmasters International he has systematically built his self-confidence and communicating ability in line with Larry Storeteling.... In one decreases and the other doubles too Year 10 take the of. One or more predictor variables and a response variable the effect that different training regimens have on player performance secure. Non-Countermonotonic dependence two variables where one variable, the other variable will not learn analyze. And circles, Problems, and often monotonic relationships, in essential,... Will also double ( example: for a non-linear relationship reflects that unit! Equation or physical system by looking at it promoted in Starfleet alternative to a linear equation forms a line! Two plots in this machine is: a guy is skating up a ramp 1.5m high 2m long monotonic,! That there is no relationship between the variables these examples of non linear relationships in real life you should start by creating a scatterplot of variables... The examples of nonlinear recurrence relations are the logistic map and the other variable will not bring! Exchange Inc ; user contributions licensed under cc by-sa points are plotted in Panel ( b.! ] linear relationships are most common, but variables can also have a nonlinear curve.. Ones here, we look at the UCR time series Classification Archive examples of non linear relationships in real life the segment. Variable ( y ), is known as dependent variable or outcome
The following is multiple choice question (with options) to answer.
Which relationship is accurate? | [
"rabbits always eat producers",
"plants eat rabbits which eat plants",
"rabbits eat plants which eat plants",
"plants eat plants which eat plants"
] | A | a consumer can not produce its own food |
OpenBookQA | OpenBookQA-2129 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is the most accurate statement? | [
"Brittney can receive minerals by standing in the sunlight",
"Ted can receive calories by standing in sunlight",
"Jeff can receive protein from sunlight",
"Kelly can receive vitamins by soaking up sunny rays"
] | D | Vitamin D heals bones |
OpenBookQA | OpenBookQA-2130 | light, history, speed
% WaaeaacaaIXaGaey4kaSYaaSaaaeaacqqHuoarcaWGwbaabaGaam4q
% aaaaaiaawIcacaGLPaaacaWGMbWaaSbaaSqaaiaad+gaaeqaaaaa!3BBB!
$$
I hashed through the numbers myself and I got an answer of about 10 minutes more or less from 42 hours depending on which way the earth is heading with reference to Jupiter. Ole Rømer did not measure a change in the frequency of light. He measured an apparent change in the orbital period of Io, one of Jupiter's moons.
The orbit of Io can be measured very accurately by observing when it enters or leaves the shadow of Jupiter. When the Earth is moving away from Jupiter, Rømer noted that the orbit of Io appeared to be very slightly longer than when the Earth was moving parallel to Jupiter.
Suppose the orbital period of Io is $p$ seconds. If you are not moving and you observe an eclipse at time $t$, the next eclipse will be at time $t+p$. However, if you are moving away from Io, the next eclipse will be seen at $t+p+x$, where $x$ is the time that light takes to travel from your position at time $t$ to your position $p$ seconds later.
The delay over a single orbit was too small for him to measure (about 30 seconds). But the delay was cumulative, and over about 30 orbits of Io, the orbit was delayed by about a quarter of an hour. He noted:
The following is multiple choice question (with options) to answer.
How long would it take for you to notice the sun's movement? | [
"half an hour",
"15 seconds",
"half a minute",
"one nanosecond"
] | A | the Earth rotating on its axis causes the sun to appear to move across the sky during the day |
OpenBookQA | OpenBookQA-2131 | reproduction
Title: Why are so many species reproducing late this year? Hope this question is OK for this site, couldn't see where else to ask it.
We've spent a few days out in the countryside recently, and have been very surprised at how many species appear to have very young offspring so late in the season. I was always under the impression that the vast majority of animals and fish produced young in the spring (March/April).
For example, we saw tadpoles, fluffy (ie obviously very young) coots and weeny minnows. I would have expected that all of these would have been born/laid a good 3 or 4 months ago, and so would be more mature by now.
Caveat: We didn't do a scientific study, this is just a strong impression we got from days out in north west England. It's hard to say without more information, but one substantial possibility is that you are mistaken that species are reproducing late - that's a problem with anecdotal rather than scientific data!
Additionally, species you mention like the common coot can attempt multiple broods where the season is long enough. Wikipedia specifically mentions Britain:
Eurasian coots normally only have a single brood each year but in some areas such as Britain they will sometimes attempt a second brood
The same could be true for species of frogs/toads and fish, so without knowing specific species it can't be known whether these are species reproducing again or species reproducing late.
The following is multiple choice question (with options) to answer.
A creature may reproduce during | [
"a stage of maturity",
"a concert on stage",
"a stage of denial",
"a staging of hosts"
] | A | reproduction is a stage in the life cycle process |
OpenBookQA | OpenBookQA-2132 | botany, plant-physiology
Title: Are fairy rings documented as a growth pattern in ferns? I planted an Onoclea sensibilis, a single plant, in my garden. After the first season, there was signs that a fairy ring was forming. A few years later it was mostly complete, but then was obscured in the following years by the growth of the next generation ferns on the ring.
I have not seen any documentation in my field guides that sensibilis or any other fern creates a fairy ring.
I would believe that the fairy rings would be rare in the field.
Where would I find documentation on fern fairy rings? As this was the only result I could find about Onoclea sensibilis fern ring I wanted to add a reference to a wild fern ring I found of the species. This was found in the fall, 2022, in WV during a hike. I do not know the age of the patch of ferns.
This response, I hope, should act as an answer to the question for documentation of a sensibilis fern fairy ring.
As reference and showing ownership of copyright, I originally posted this image on instagram here: https://www.instagram.com/p/CiTl_VvjXq5/
The following is multiple choice question (with options) to answer.
What would be best for healthy ferns? | [
"dog food",
"houseplant food",
"cat food",
"planted food"
] | B | food is a source of energy for plants |
OpenBookQA | OpenBookQA-2133 | electricity, electric-circuits, electric-current
I was wearing flip flops from the time I stripped off my neoprene wet suit at the car until the time I started getting shocked (my wife was wearing Birkenstocks).
I had been snorkeling for about an hour in the Pacific Ocean wearing a full body wet-suit, booties, and gloves (no hood).
I had been camping the night before and consumed quite a bit of Gatorade.
My wife had only been wearing a spring suit and gloves, no booties.
There was another receipt that had been left in the machine (maybe someone else had been shocked as well and decided it wasn't worth the risk of going after it?)
I can't think of anything else relevant. Any insights into what was going on here would be welcome. I tried calling the maintainers of the machine but couldn't get through (this was before I found out that I seemed to be the only one affected).
Thanks!
She tried touching the machine in various places, again nothing. I inadvertently touched her hand while she was touching the machine and then suddenly she felt it too.
From this it is evident you were a good conductor to the ground.
You later say :
We came back out 15 minutes later after drinking our hot chocolate and tried to reproduce the phenomenon with no luck.
So no charge was passing through you any longer?
15 minutes is too little a time to change your conductivity. It could be a combination of an intermittent fault in the circuit and your conductivity at that time. You should alert their maintenance to be on the safe side.
The following is multiple choice question (with options) to answer.
Just a few days ago, Beth waded into her family's pond. Now when she stepped off the bank the pond was hard and she could walk on the surface. What happened? | [
"a cold front had moved into the area",
"The pond had drained into an underground river",
"There was a lot of algae on the pond's surface",
"It had rained the night before"
] | A | freezing causes a solid to form |
OpenBookQA | OpenBookQA-2134 | python, game, adventure-game, python-2.x
itemscanbeobtained.append('Bait')
itemscanbeobtained.append('Bird Nest')
for i in range(random.randint(0, 3)):
retlist.append(random.choice(itemscanbeobtained))
return retlist
The following is multiple choice question (with options) to answer.
A pigeon is hungry so it snags a slice of pizza off a table using its | [
"wing",
"teeth",
"beak",
"leg"
] | C | a beak is used for catching prey by some birds |
OpenBookQA | OpenBookQA-2135 | the-moon, moon-phases
Title: Red cresent moon Yesterday night i witnessed something very strange when i looked outside the window. I saw the moon (crescent) but it was dull red and right on the horizon ,which is strange considering that it is usually on the upper right of the night sky and white in colour. On further inspection with my binoculars i noticed it was lowering down until it was hidden by the mountain range (5km away) next to my building, this all occurred within a few minutes (about 5).
Tonight i saw the moon (crescent) had again returned to its normal position.
Please explain the cause for this, i'm completely baffled!
(Sorry for the poor wording, i'm not familiar with all the astronomical terms!) The dull red color has been due to atmospheric causes, like the reddish sun close to sunset. There hasn't been an astronomical reason for the reddish color.
A few days after New Moon moonset occurs short after sunset, so you won't see the Moon high over the horizon at those evenings. With each day the Moon is a little higher above the horizon after sunset. It's hence less close to the horizon at the same time of the day. Less close to the horizon means less atomospheric absorption/scattering responsible for the dull red color, assuming the same weather conditions.
At Full Moon the Moon is at the opposite side of the Sun relative to Earth. Moon is then rising shortly after sunset.
The following is multiple choice question (with options) to answer.
The moon will show a different type of this each week. | [
"locale",
"rate",
"fullness",
"scent"
] | C | a different moon phase occurs once per week |
OpenBookQA | OpenBookQA-2136 | zoology, ecology, population-biology, ecosystem, predation
Title: Predator prey interaction I went through a line in my textbook which read:
"But for predators, prey species could achieve very high population densities and cause ecosystem instability."
I was not able to understand the meaning 'but for predators'. Can anyone please help me to interpret it's meaning?link to page where this line is mentioned
Edit: In terms of biology, I was unable to understand the meaning of the sentence, and I wanted to make sure that I don't misunderstand things... And this is why I posted the question.. I feel that the answer given is correct and in case, you find better explanation, please do post. I disagree with GForce's explanation; the meaning is not that growth of prey populations causes instability in predator species.
The sentence is merely saying that without predation, prey population growth is more likely to be at a level which leads to ecosystem instability. The term "but for predation" means "if it wasn't for the effects of predation". In other words:
"Ecosystem instability can occur when population growth of some species goes unchecked by predation."
See here for more explanation, where this example comes from in which it says that running a red light caused a crash:
"but for running the red light, the collision would not have occurred"
Biologically this makes sense in the sentence you show; without predators a species is limited by its supply of resources, and it can use these resources at an unsustainable level, whereas if you add predators to the mix there is additional extrinsic effects on population size, not determined by ecosystem properties such as space or nutrients.
The following is multiple choice question (with options) to answer.
Which of the following would be considered a predator? | [
"grizzly bear",
"moose",
"salmon",
"lobster"
] | A | predators eat other animals |
OpenBookQA | OpenBookQA-2137 | organic-chemistry, physical-chemistry, biochemistry, alcohols
Title: Storage of Urine Not all may be favorable to this project, but I will explain what I am trying to do. I work at home, and instead of walking a moderate distance to the bathroom and loosing my focus, I've been, at times, peeing in a 3 Quart Poland Springs water bottle. If you take offense at this, please do not continue reading except to be helpful in the scientific goal. I know this subject won't suit many types of people, so just ignore it if that is your case.
I noticed first of all that urine is not at all as sterile as people say that it is. The rate of growth of bacteria is relatively slow, but as a precaution, I found the need to use additional measures to prevent the growth of bacteria. I settled on the following method: I have two bottles and I add to each bottle about enough salt as can be soluble in the urine and sometimes maybe a little more. The one bottle then fills up throughout the day and is emptied, washed, and refilled with salt. The salt helps to kill the bacteria which would be lingering in the empty bottle. The next day, the bottle stays empty and the other is used.
I would add that I discovered that the bacteria (without the salt) does not usually grow unless the bottle is left with urine for two days. After this, however, that same bottle (without the salt) would retain the bacteria and immediately grow, if used again.
This system works relatively well, so long as it is done every day. It will even withstand 2 days with only moderate growth. (If I should leave it by mistake for longer it can get ugly). Nevertheless, I am still looking to improve upon this. One reason is that, if I drink less water or relieve myself normally, the bottle does not fill in one day. I am looking for someone with knowledge of chemistry to help me find a substance that can be added to this solution which fits a number of common sense criteria. I will also add a list of the substances that I have tried or already considered.
Necessary qualities
The following is multiple choice question (with options) to answer.
A person wanting to dry their shoes using a resource that is unlikely to expire could use | [
"a breeze",
"a tree",
"a river",
"a snowbank"
] | A | wind is an inexhaustible resource |
OpenBookQA | OpenBookQA-2138 | geology, geophysics, core
Title: How long until Earth's core solidifies? How much longer does Earth have until the core turns solid?
Does global warming change these estimates at all? Global warming has to do with the surface only, and at best involves changes of 20 degrees at the outside extreme, in comparison to the earth's core, which is as hot as the surface of the sun.
For complete accuracy, and to reflect what a commenter has pointed out, the inner core is solid already, but this is because of the extremely high pressure of the overlying layers of the outer core (which IS liquid), and the mantle. See the Wikipedia articles concerning the Inner Core, and the Outer Core. Note that it is the outer core which creates the earth's magnetic field.
The answer is that the earth's core will never be solid. And I do mean NEVER. Now, that being said, there is only one way it could ever happen and that is if the earth happened to get thrown out of its orbit to become a nomad planet. Then it might have time for its core to cool.
The reason I say this is because it will take longer for the earth's core to turn solid than it will take for the sun to run out of nuclear fuel and expand to engulf the earth. At that point, the earth will be vaporized as it spirals out of its orbit into the sun. The core would soon turn into incandescent gas. This will occur something like 4 to 5 billion years from now.
If by some chance the earth were to become a nomad planet, free to cool in its own good time, then it would take a long long time. See Energetics of the Earth by John Verhoogen, available online via Google Books.
The following is multiple choice question (with options) to answer.
What might cause a change in the Earth's surface? | [
"Plastic Bottles",
"Happiness",
"Love",
"Sadness"
] | A | natural events usually cause changes to Earth 's surface |
OpenBookQA | OpenBookQA-2139 | ##### Motivating Questions
• In a setting where a situation is described for which optimal parameters are sought, how do we develop a function that models the situation and use calculus to find the desired maximum or minimum?
Near the conclusion of Section 3.3, we considered two examples of optimization problems where determining the function to be optimized was part of a broader question. In Example 3.3.4, we sought to use a single piece of wire to build two geometric figures (an equilateral triangle and square) and to understand how various choices for how to cut the wire led to different values of the area enclosed. One of our conclusions was that in order to maximize the total combined area enclosed by the triangle and square, all of the wire must be used to make a square. In the subsequent Activity 3.3.4, we investigated how the volume of a box constructed from a piece of cardboard by removing squares from each corner and folding up the sides depends on the size of the squares removed.
Both of these problems exemplify situations where there is not a function explicitly provided to optimize. Rather, we first worked to understand the given information in the problem, drawing a figure and introducing variables, and then sought to develop a formula for a function that models the quantity (area or volume, in the two examples, respectively) to be optimized. Once the function was established, we then considered what domain was appropriate on which to pursue the desired absolute minimum or maximum (or both). At this point in the problem, we are finally ready to apply the ideas of calculus to determine and justify the absolute minimum or maximum. Thus, what is primarily different about problems of this type is that the problem-solver must do considerable work to introduce variables and develop the correct function and domain to represent the described situation.
Throughout what follows in the current section, the primary emphasis is on the reader solving problems. Initially, some substantial guidance is provided, with the problems progressing to require greater independence as we move along.
##### Preview Activity3.4.1
According to U.S. postal regulations, the girth plus the length of a parcel sent by mail may not exceed 108 inches, where by “girth” we mean the perimeter of the smallest end. What is the largest possible volume of a rectangular parcel with a square end that can be sent by mail? What are the dimensions of the package of largest volume?
The following is multiple choice question (with options) to answer.
A person wanting to continue to use a man-made box will | [
"throw it in the trash",
"put it in the garbage",
"burn it in a fire",
"find new uses for it"
] | D | something reusable can be used more than once |
OpenBookQA | OpenBookQA-2140 | algorithm, go, concurrency, dining-philosophers
// reserve a slot in the channel for eating
// if channel buffer is full, this is blocked until channel space is released
pPhilo.host.requestChannel <- pPhilo
pPhilo.numEat++
fmt.Printf("starting to eat %d for %d time\n", pPhilo.idx, pPhilo.numEat)
time.Sleep(time.Millisecond)
fmt.Printf("finishing eating %d for %d time\n", pPhilo.idx, pPhilo.numEat)
pPhilo.rightCS.mu.Unlock()
pPhilo.leftCS.mu.Unlock()
wg.Done()
}
}
func main() {
var wg sync.WaitGroup
host := Host{
eatingChannel: make(chan *Philo, numEatingPhilo),
requestChannel: make(chan *Philo),
quitChannel: make(chan int),
eatingPhilos: make(map[int]bool),
}
CSticks := make([]*ChopS, numCS)
for i := 0; i < numCS; i++ {
CSticks[i] = new(ChopS)
}
philos := make([]*Philo, numPhilo)
for i := 0; i < numPhilo; i++ {
philos[i] = &Philo{idx: i + 1, numEat: 0, leftCS: CSticks[i], rightCS: CSticks[(i+1)%5], host: &host}
}
go host.manage()
wg.Add(numPhilo * eatTimes)
for i := 0; i < numPhilo; i++ {
go philos[i].eat(&wg)
}
wg.Wait()
host.quitChannel <- 1
}
The following is multiple choice question (with options) to answer.
A person eating a watermelon slice will perhaps want to take time during eating to | [
"plant a garden",
"build a house",
"remove black pips",
"climb a mountain"
] | C | fruit contains seeds |
OpenBookQA | OpenBookQA-2141 | ornithology, kidney
Back to worrying about the mammal-centric thinking: there is a causal implication in both the original and my edited version that is not warranted, which is that the anatomy of the loops of Henle is somehow determining the nitrogen excretion strategy that birds use. It's equally reasonable to presume that birds don't need long loops of Henle since they evolved an alternative excretion mechanism that makes it unnecessary to concentrate urine to a great degree.
The "trick" of that alternative excretion mechanism is using uric acid and excreting a paste. Because uric acid crystalizes and comes out of solution, it doesn't "count" toward osmolarity of the urine, it's excreted as a solid. Birds don't need to remove water to crystalize uric acid, and don't need to use water to flush it out at all, it falls out of solution on its own because it's not very soluble. You could add a bunch of extra water and it would still stay mostly solid rather than dissolving.
So back to your original question: how do birds concentrate their urine? Well, pretty much the same way we do as far as the kidney goes. They also pull some water back in through the cloaca before urine is released, similar to how mammals pull water in from stool in the large intestine. The important difference is not how birds concentrate their urine (because urine concentration isn't a goal/need in itself), but rather how birds excrete nitrogen waste. By not flushing soluble nitrogenous waste with water in the first place, they don't have as much urine to concentrate, so it's less important for them to be very efficient in doing so.
The following is multiple choice question (with options) to answer.
Hummingbirds drink nectar from flowers, and when they leave the flower | [
"they turn bright purple",
"they fall to the ground",
"they bring special dust with them",
"they eat small birds"
] | C | when pollen sticks to a hummingbird , that pollen will move to where the hummingbird moves |
OpenBookQA | OpenBookQA-2142 | electricity, electric-circuits, electrons, electric-current, charge
Title: Electrons in an electric circuit , its movement and power delivered Does an electrical appliance convert electrons into its respective work , I mean is electron being consumed by appliance (say bulb ) and then this mass gives us energy.
or the same number of electron , just revolve around the circuit, then from where does power comes from, Electrons have charge and so when there is a potential difference across a circuit, this charge moves through it. In an incandescent light bulb, there is a high resistance, meaning that there are many atoms with which the charges collide, transferring some of their kinetic energy. No electrons are being "consumed" by the light bulb, i.e. the number of electrons in the circuit does not change. The ability of the charges to do work is because of a potential difference, which can be achieved through a number of means, e.g. using voltaic cells or electromagnetic induction.
To gain a better idea of why potential difference moves charges, consider two isolated point charges of opposite charges, one positive and one negative. If you pull the negative charge away from the positive one, you are doing work on it in the form of potential energy, as you are opposing the electric field of the positive charge. If you let go, the negative charge will convert this potential energy into kinetic energy, as it is attracted to the positive test charge. A potential difference across a circuit, albeit simplified, essentially does this – it brings electrons from a higher potential to a lower potential, converting potential energy into the kinetic energy in the process.
The following is multiple choice question (with options) to answer.
Which of the following comprises the energy that fuels a toaster? | [
"microns",
"protons",
"electrons",
"TRONs"
] | C | electricity is made of moving charges |
OpenBookQA | OpenBookQA-2143 | optics, electromagnetic-radiation, visible-light, reflection, geometric-optics
Title: We know that a window can actually reflect light. But if the window has some dirt sticking to it, the image we see sometimes get magnified. Why? Well, I was traveling in a bus yesterday and saw this occur. The board that separates the passengers from the driver's had something written on it and I saw that the window that was a few meters away from the board reflected all of the things written.. But the window had some dirt on the part where I saw the image of the writings... And, they appeared to be enlarged just at the point where dirt was present. The open spaces between dirt particles each acts like a "pinhole camera" to magnify the image behind the dirty glass pane. The magnification is slight but noticeable. Try this experiment: make a small triangular hole shape by putting three fingertips together so as to leave a gap at their intersection. by pressing your fingertips together, you can make the size of the hole shrink; by relaxing them, you can make the hole larger.
That hole will act as a pinhole camera. now look through the hole at your computer screen from about 24 inches away and vary the hole size. you will find a certain diameter at which the image you see through the hole will get sharper and the text on the screen will become easier to read.
The following is multiple choice question (with options) to answer.
A person can see a large pollutant source when looking at | [
"trash heaps",
"land tracts",
"bottle deposits",
"water droplets"
] | A | an landfill is a source of pollution |
OpenBookQA | OpenBookQA-2144 | infection, amphibians
Title: What is this toad suffering from? Myiasis or chytridiomycosis? I found this toad on Aug. 29th at this location: position on osm
I think it is a bufo bufo, approx. 10 cm long. The nostrils seemed to be completely filled with a grey matter and from the activity of the floor of the mouth it apparently tried to breathe againgst this obstruction. It probably had enough oxygen via its skin though.
I tried to remove the obstruction using a blade of grass but this seemed to produce some pain as the toad closed its eyes on contact, so I stopped. The skin looked fairly normal and the toad was able to walk away after a while.
I can think of two causes for this condition.
Batrachochytrium dendrobatidis infestation
Lucilia bufonivora larvae
I could not see properly, if there were any larvae or unhatched eggs inside the nostrils, but as the rest of the skin seemed unharmed I assume the latter.
Is my assumption valid or is there even a third possibility? It is a female Bufo Bufo and you are right, there are toad fly (Lucilia bufonivora) larvae/eggs inside her nostrills. These flies lay their eggs inside toads' nostrills (specifically on Bufo Bufos) and the larvae start eating them. Sadly this disease ends up by the death of toad. They slowly eat nostrills, then mouth, eyes, and all the head.
Here's a photo of a male bufo bufo, without a head. Someone found it walking around at this situation. https://i.stack.imgur.com/I6twl.jpg
The following is multiple choice question (with options) to answer.
A dog outside could be shuddering uncontrollably. Which of these could be related? | [
"they were scared by their own shadow",
"they ate too much food",
"white precipitation is falling and it's windy",
"they are very tired"
] | C | shivering is when an animal creates heat by shaking to keep the body warm |
OpenBookQA | OpenBookQA-2145 | # Thread: physics tourist & bear problem
1. ## physics tourist & bear problem
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
2. Originally Posted by rcmango
another easy one i think:
A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.5 m/s. The car is a distance d away. The bear is 27 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
how many meters?
thanks alot.
The maximum value of d is such that the bear gets to the car at the same time the tourist does.
So set up a coordinate system such that the bear is at the origin and positive x is in the direction from the bear to the tourist.
Both are moving at a constant speed. The bear has to cover 27 + d meters in the same time the tourist covers d meters.
So for the tourist:
[tex]d = v_t t = 3.5t[tex]
Thus
$t = \frac{d}{3.5}$
For the bear:
$27 + d = v_b t = 6 \left ( \frac{d}{3.5} \right )$
Now solve for d.
-Dan
3. Hello, rcmango!
Another approach . . .
A tourist being chased by an angry bear is running in a straight line
toward his car at a speed of 3.5 m/s. .The car is a distance $d$ meters away.
The bear is 27 meters behind the tourist and running at 6.0 m/s.
The tourist reaches the car safely.
What is the maximum possible value for $d$?
The tourist has a 27-meter headstart.
Relative to the tourist, the bear has a speed of 2.5 m/s.
To cover 27 meters, it takes the bear: . $\frac{27}{2.5} \:=\:10.8$ seconds.
The following is multiple choice question (with options) to answer.
A person running away from an attacking black bear will note that as they run faster, the bear | [
"looks minuscule",
"looks average",
"looks bigger",
"looks younger"
] | A | as distance to an object increases , that object will appear smaller |
OpenBookQA | OpenBookQA-2146 | quantum-mechanics, quantum-information, superposition
When the compass needle points north, that is like a qubit being in the state $\lvert 0\rangle$, and when the compass needle points east, that is like a qubit being in the state $\lvert 1\rangle$. But a compass needle can also point northeast. The direction northeast is neither north nor east, but it is a superposition of equal parts north and east: if you add a north-pointing vector and an east-pointing vector of equal magnitude, you will get a vector that points northeast. Similarly, the qubit state $\frac{1}{\sqrt{2}}(\lvert 0\rangle + \lvert 1\rangle)$ is neither $\lvert 0\rangle$ nor $\lvert 1\rangle$, but it is a superposition of equal parts $\lvert 0\rangle$ and $\lvert 1\rangle$.
The following is multiple choice question (with options) to answer.
A person using a compass knows that the needle points north, so the person wanting to go south will | [
"walk towards where the needle points",
"walk opposite where the needle points",
"walk away from the compass",
"forget to use the compass"
] | B | a compass is a kind of tool for determining direction by pointing north |
OpenBookQA | OpenBookQA-2147 | solvents, solubility, melting-point, phase
Similarities:
In each case, forces between the particles that comprise the solid are disrupted and that takes energy. (Whether it’s chemical bonds or intermolecular forces depends on the process and on the solid and on your definitions. (See this question.) But melting (rare exception noted in previous comments) is endothermic and dissolving can be either endo- or exo-thermic.
In each case you end up with a liquid. Macroscopically, if you walked into a room and saw the liquid on the table, it would be difficult to say whether this liquid came from a solid that had melted or a solid that had dissolved in a solute and made a solution.
But it would be very easy to determine which you had experimentally in a “dozen” different ways.
Both melting and dissolving require interaction among groups of atoms, molecules, or ions.
There are probably more differences that could be given (how to handle thermodynamic calculations, complexity of the system etc.), and possibly more similarities, but that's enough for me on this topic.
The following is multiple choice question (with options) to answer.
Which event includes melting? | [
"making ice",
"cooking in butter",
"cutting carrots",
"buttering bread"
] | B | melting means changing from a solid into a liquid by adding heat energy |
OpenBookQA | OpenBookQA-2148 | java, algorithm, linked-list, matrix
public void rotateBy(int steps, RotationDirection direction){
for(Node<I> shellHead : shellNodeCounts.keySet()){
int shellNodeCount = shellNodeCounts.get(shellHead);
shellHead.rotate(direction, steps % shellNodeCount);
}
}
The following is multiple choice question (with options) to answer.
One way to recycle is by turning | [
"plastic into food",
"plastic into shoes",
"plastic into trees",
"plastic into rivers"
] | B | An example of recycling is using an object to make a new object |
OpenBookQA | OpenBookQA-2149 | This lets them bring a 15th bar and catch the train with less than 5 minutes to spare.
It is not possible to move all 16 bars.
Consider the total distance that each person moves, in each direction, carrying each possible number of bars. For example $$R_2^+$$ is the total distance that Rod moves forward while carrying 2 bars. We can set up a system of equations. Both Rod and Lia must move a net distance of $$1$$ mile forwards: $$R_0^+ - R_0^- + R_1^+ - R_1^- + R_2^+ - R_2^- = 1 \\ L_0^+ - L_0^- + L_1^+ - L_1^- = 1$$ Both of them must spend less than $$370$$ minutes moving (note we have taken the reciprocals of their speeds in minutes per mile): $$20(R_0^+ + R_0^-) + 30(R_1^+ + R_1^-) + 60(R_2^+ + R_2^-) \le 370 \\ 30(L_0^+ + L_0^-) + 40(L_1^+ + L_1^-) \le 370$$ Finally, the total net distance moved by all the bars must be $$16$$ miles forwards: $$R_1^+ - R_1^- + 2(R_2^+ - R_2^-) + L_1^+ - L_1^- = 16$$ And of course each distance must be nonnegative.
Next (thanks to RobPratt) we multiply these equations by $$\frac{1}{2}$$, $$\frac{3}{7}$$, $$\frac{1}{40}$$, $$\frac{1}{70}$$, and $$-1$$ respectively, and sum them, yielding:
The following is multiple choice question (with options) to answer.
A person can get to point a to point b faster than by walking if they | [
"make a big donation",
"hope for several years",
"use continuous motion on a device",
"plan for expensive hotels"
] | C | pushing on the pedals of a bike cause that bike to move |
OpenBookQA | OpenBookQA-2150 | electromagnetism, electrostatics, electricity, everyday-life
Title: Can sugar be affected by a magnetic field? While I was making a morning coffee at work, some sugar from the spoon started to fly away, seemingly towards some foam cups. Can this be explained by magnetism? Electro-magnetism is a good guess, simply because it's the only force you commonly see that's powerful enough. It's not very useful as an explanation, though, because almost everything you see around you is due to electro-magnetism (e.g. the way the spoon holds together in the first place, or the light that allows you to see the sugar, or the way the water "sticks" to having a fluid surface, or the way the individual atoms of the sugar stick together...). The real question is "What kind of EM is responsible?"
It's not ferro-magnetism (the kind you see with old-school fridge magnets) - neither the foam nor the sugar are ferro-magnetic. It's not para-magnetism either.
It's not due to molecular nor atomic bonds (the kind that holds molecules together, or the residual force that causes e.g. hydrogen bridges) - the distance involved is too large.
It's not dia-magnetism (remember those frog levitation videos?). That would require massive magnetic fields.
I could go on, but there's plenty of other cases that obviously don't apply, so let's skip to the end:
The interesting point is that plastics are usually electric isolants. This is very important, because it means that when they acquire a charge imbalance, it's not equalised very quickly - the current can't flow readily. This means that it's possible for one side to have a slight positive charge, while the other side has a slight negative charge (in a metal, in contrast, the charges would "mix" to maintain an overall neutral charge).
The following is multiple choice question (with options) to answer.
Which of the following was made from sugar? | [
"oxygen",
"meat",
"bread",
"flour"
] | C | carbohydrates are made of sugars |
OpenBookQA | OpenBookQA-2151 | evolution, species
Title: Parents that eat their own children I am told that there are some species, like fish or rabbits, that if let, will eat their own children. If this is true, how does a species like this exist? Shouldn't the fact that they kill their own lineage make them nonviable? Yes, it is true.
Prairie dogs
Prairie dogs for example are known for frequent infanticides.
Many other species kill their babies too
But of course, such behaviour also exists in other lineages such as grey langurs, gerbilles, lions, giant water bugs and Bottlenose dolphins (just to cite a few examples).
How does that evolve
It will be impossible to provide a complete universal explanation to this behaviour because the evolutionary processes causing this behaviour varies from lineage to lineage. For examples, in lions, only males kill young of the females that are still nursing and they do so when taking over a new harem only. In prairie dogs, mothers cause infanticide preferentially on others' babies but also on their own babies.
Going into the details of how such behaviour evolves in every specific lineage would probably require writing an intro on kin selection and other fields of evolutionary biology which is way too much for a single post. You may want to have a look at the wikipedia article infanticide for a start.
Shouldn't the fact that they kill their own lineage make them nonviable?
Of course, they don't kill all the babies. Only a fraction of them!
The following is multiple choice question (with options) to answer.
One day a zebra dies. Zero baby zebras were born in the herd on that day. | [
"the zebras traveled a hundred miles that day",
"a new life was created",
"the population went down",
"the population of the herd increased"
] | C | if an organism dies then the population of that organism will decrease |
OpenBookQA | OpenBookQA-2152 | geophysics, sedimentology
Title: Does dirt compact itself over time? If so, how does this happen? If I were to bury something 10 feet (~3 metres) underground, with loose soil on top, would the ground naturally compact itself over time, until whatever I had buried has dirt tightly pressing against it on all sides?
What if I buried it 50 feet (~15 metres) underground?
If it exists, what is this compaction process called and how does it happen? Soil is a collection of various sized minerals grains, of various types of minerals produced by the weathering of rock. Typical soil minerals are clays, silts and sands.
The properties and behavior of different soil types depends of the composition of the soil: the proportion of clays, silts and sand in a soil. Sandy soils are well draining and clayey soils are sticky.
Between the grains of minerals that comprise a soil are spaces, called pores or pore spaces. The pores can be filled with either water or air, depending the location of water tables and wetting events like rain, snow melts or other forms of water inundation.
The density of a soil is dependent on the degree of compaction of the soil. For to a soil to be compacted, a stress has to be applied to the soil to realign the grains of soil which reduces the total volume of the pores and reduces the amount of air within the pores.
Consolidation of a soil occurs when pore space is reduced and water in a soil is displaced due to an applied stress.
Regarding having something buried and soil compacting around it over time, yes that will occur but it is a question of how much stress the soil experiences, the duration of time and the nature of the soil - sandy or clayey. Something buried for a day without any stresses not much will happen. But, something buried for thousands of years with people and animals walking over it, rain falling on the soil, vibrations from nearby human activity and an occasional earthquake all add to the stresses the soil will experience and increases the degree of compaction or consolidation over time.
The following is multiple choice question (with options) to answer.
Which would be formed by layering sediment over time? | [
"ammonite",
"shells",
"ominous",
"ammunition"
] | A | fossils are formed when layers of sediment cover the remains of organisms over time |
OpenBookQA | OpenBookQA-2153 | genetics, gene-expression, human-genetics, mitochondria, gene
Title: Father with mutated mtDNA- why isn't his offspring at risk? Mothers transmit their mitochondria (and therefore mtDNA) to their offspring and fathers don't. Lets assume that father had a mutation of the gene that encodes mtDNA, would then be his offspring at risk? Why?
I also found the following statement:
"The current genetic advice is that fathers with mtDNA mutations are at no risk of transmitting the defect to their offspring."
How can that be true? Is it because of gene silencing?
Thank you in advance!
...would then be his offspring at risk? Why?
No. Generally speaking, fathers do not pass on their mtDNA (Mitochondrial DNA).
Why? Because the mitochondria present in oocytes (egg cell) is the mother's, as every oocyte directly inherits the mother's mitochondria when they are made in the reproductive organs. The mitochondria that the sperm from the father carry to the egg do not enter the egg cell or are destroyed in the process.
It's also worth mentioning that, in general, mtDNA does NOT reside in the nucleus of cells, but in the mitochondria itself. It is not condensed during cell division, it is not spliced during Meiosis II, and it does not undergo recombination with another cell's mtDNA. Instead, when a cell divides, each cell takes about half of the mitochondria present in the cell and maintains them. That way only the mitochondria present in the cell before division will be inherited by the daughter cells, and thus only the maternal mitochondria present in oocytes (egg cells) before sperm instigate cell division will be inherited by any offspring.
The following is multiple choice question (with options) to answer.
A son inherits a feature from his father through DNA, so the son is likely to have his dad's | [
"sense of humor",
"temper",
"aversion to garlic",
"nose"
] | D | inheriting is when a inherited characteristic is passed from parent to offspring by DNA |
OpenBookQA | OpenBookQA-2154 | homework-and-exercises, newtonian-mechanics, friction, harmonic-oscillator, differential-equations
If the spring is compressed and the force due to the spring is greater than the frictional force the motion will continue when the mass stops for the first time and a similar analysis can be made with the direction of force $T$ reversed.
The following is multiple choice question (with options) to answer.
A person loves spring, and it has just passed by. They will enjoy it again the next time | [
"the stars go out",
"most irises begins budding",
"a week goes by",
"the days grow shorter"
] | B | each season occurs once per year |
OpenBookQA | OpenBookQA-2155 | zoology, ethology, sociality
Canfield, J., Hansen, M. V., Becker, M., & Kline, C. (1998). Chicken Soup for the Pet Lover’s Soul. Deerfield Beach, FL: Health.
The following is multiple choice question (with options) to answer.
A person who wants to raise alligators will need a supply of food such as | [
"hay",
"grass",
"corn",
"bass"
] | D | alligators eat fish |
OpenBookQA | OpenBookQA-2156 | homework-and-exercises, kinematics
In order to conclude that the runner with the shorter time was indeed faster...
and am wondering whether this ought to be interpreted as a statistical hypothesis test. If you say that the null hypothesis is "they are going at the same speed, the tracks are different length" and the alternate hypothesis is "the track length alone cannot explain the difference in time", then you need to make a decision about the confidence level with which you reject the null hypothesis. So you need to ask yourself -
For a given velocities $v_1, v_2$ with error $\Delta v$, what is the track length difference for which $v_1 > v_2$ with > 95% confidence
That means we are looking at the error in velocity (which I estimated above at 0.07%) and choose the track lengths $T_1, T_2$ such that the velocity calculated from the times is different. This is a slightly different calculation than I had above, but it argues for rounding up the answer, rather than claiming that the mean difference is exact. To go from 50% to 95% confidence you need mean + 1.28 $\sigma$ (one sided confidence interval).
The following is multiple choice question (with options) to answer.
Winning a race requires you to be reach the finish line in a before your opponents, so using what will measure how much faster you win or lose by? | [
"a rabbit",
"a cup",
"a cotton swab",
"a stopwatch"
] | D | a stopwatch is used to measure time |
OpenBookQA | OpenBookQA-2157 | classical-mechanics
the other car hits you and starts compressing your car's crumple zone.
the collision force exceeds your braking force and your car starts accelerating. Your car's crumple zone is still being compressed.
the crumple zone is fully compressed so both cars are now moving at the same speed and your brakes are slowing both cars.
During phase 1 your car is stationary so you feel no force. If the collision is low speed the other car may come to rest before your car starts to skid, and you feel no force at all.
However all but the most trivial collisions are likely to apply more force than your brakes can resist, and you enter phase 2. To calculate the force you feel in phase 2 is quite involved as you'd have to know the force distance curve for compression of the crumple zone. I did Google to see if I could find this data, but without success. Anyhow, it should be obvious that the force during phase two will be less than you'd feel if the brakes weren't on.
Phase three is interesting because it's where you get the whiplash. Assuming your headrest is properly adjusted your head won't move much in phase two. However when you enter phase three your own brakes will jerk you forward. To reduce this (and as above assuming there are no 18 wheelers around) you should release the brakes.
So for low speed collisions you should leave the brakes off, but for high speed collisions hit the brakes during the collision and release them as soon as the two cars have stopped moving relative to each other.
Having said all this, the collision you describe happened to me a few years ago (I'm sure it's hapened to lots of us) and I hit the brakes and held them on. I'm happy to report I suffered no harm, though my car was a write-off. I would advise my children to always hit the brakes and leave them on. Risking whiplash is better than being pushed across the junction or into the back of the car in front of you.
The following is multiple choice question (with options) to answer.
Which of these effects are most likely to happen if someone brakes to avoid hitting a deer? | [
"extra money given",
"car laughs",
"deer smiles",
"tires worn down"
] | D | braking can cause skidding |
OpenBookQA | OpenBookQA-2158 | food-chemistry
popcorn (kernels)
honey (jar of)
sugar (most forms)
alcohol (spirits like vodka, whiskey)
dried beans, dried lentils
I would not be planning to eat any of these stored for 25 years myself. And in general I'd suggest testing the items before trying them after 25 years or more (if you feel you must).
I would not expect cans or glass or plastic bottles of soda to be in good shape after anything like 25 years. The plastic might not survive without degrading. The can and plastic might react with the liquid over that timescale and the glass would survive but I'd be less optimistic about a sugar laced chemical soup like soda or cola not undergoing some changes. Hard to say.
If you want more info on this try this website.
Will it be ok to drink it, if it won't explode?
I would not try it. At best it soda would be flat and possibly not taste the same (chemical changes over that timescale ?) and at worst it could actually be harmful.
Exploding seems very unlikely.
Also, what about Snickers or a hamburger in a ziploc package with air sucked out of it with vacuum cleaner?
Air isn't the issue. There are bacteria that will happily live (and increase in numbers) on what's in the food. Well, it is food, after all. There are bacteria that will survive refrigeration as well. Over the timescale you're talking about I'd say it's all bets are off territory.
So: will Snickers, Hamburger in a ziploc, Bottle (or can) of Cola, all not opened, go crazy in 25 years? In 50 years?
All of those could be dangerous over such a long time period, IMO. At the very least they'd taste bad and at worst they'd kill you if you consumed them.
If so, can they go out of their packages and ruin the contents of the time capsule? If not, will it be safe to consume one of them?
Depends on the packaging. Glass would last indefinitely baring physical force or extreme of hot and cold (which might possibly cause fatigue cracking). The other wrappers would last pretty well (structurally), but 25 years is way past their design intentions. It would be a dice throw.
The following is multiple choice question (with options) to answer.
A person has a restaurant where they have a salad bar. The salad bar is packed with ice to keep food cold. The ice may last longer if | [
"the room is warm",
"salt is heavily applied",
"people eat the food",
"food is already warm"
] | B | adding salt to a liquid decreases the melting point of that liquid |
OpenBookQA | OpenBookQA-2159 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
What would an insect run from? | [
"lizard",
"insect",
"cloud",
"wind"
] | A | lizards eat insects |
OpenBookQA | OpenBookQA-2160 | cell-biology, nutrition, blood-circulation, liver
Title: How do nutrients get to the cells they need to get to? I understand the basics of digestion. I know that nutrients get absorbed by the microvilli, enter the bloodstream and travel to the liver but after all that, what is the biological mechanism that guides these nutrients to the proper receiving location? Broadly speaking, nutrients that enter the blood from the gut, and those that are released into the blood by the liver, are available to any cells that require them. So there is no "guiding to the correct location" in the sense that you suggest.
Lipids for example are present in the various lipoproteins and can be acquired from these by all cells. Iron is bound to transferrin, and any cell with transferrin receptors can internalise the transferrin and take the iron. Glucose is available in solution in the plasma, and free fatty acids are bound to serum albumin in the blood. During starvation the liver produces ketones ("ketone bodies") which are taken up by many different tissues/cell types.
The following is multiple choice question (with options) to answer.
The body of creatures may have nutrients delivered to various areas based on where | [
"hair grows",
"nails are trimmed",
"vessels travel",
"birds exist"
] | C | arteries transport nutrients throughout the body |
OpenBookQA | OpenBookQA-2161 | evolution, zoology
Let's say the environmental challenge for two different kinds of carnivore (let's call them Bogs and Dats) is to catch Mophers. Both Bogs and Dats initially have the same medium-to-short muzzles. Some Bog individuals figure out that they can dig Mophers out of their burrows, and some Dat individuals figure out that they can catch Mophers at night when the Mophers leave their burrows. Both strategies are successful. Some Bogs happen to have longer muzzles than their cousins, and find it turns out that longer muzzles work synergistically with the digging strategy, allowing Bogs to stick their noses into the Mopher burrows to grab escaping Mophers. The resulting fitness advantage results in an increase of the long-muzzle trait in further generations of Bogs. Note that in this scenario it is the adaptive behavioral strategy that creates selective pressure that favors a particular genetic adaptation.
Dats on the other hand, because of their nocturnal hunting strategy, benefit from improved night vision; and long muzzles don't provide any fitness advantage to Dats because Dats don't dig Mophers from their burrows. As long as Bogs and Dats don't hybridize, they will most likely end up with long and short muzzles respectively.
The Waddington effect, also called “Genetic Assimilation”, is somewhat more direct:
An environmental stress causes a proportion of a population to develop one or more abnormal traits, by interfering with embryological development.
If there is a selective pressure in the environment that favors some subset of those traits, individuals whose genetic makeup makes them more likely to develop that subset of traits, those individuals are likely to produce more descendants than other members of the population.
If being “more likely to develop” that subset of traits results from a weakening of genetically determined development controls that would otherwise prevent development of that subset of traits, then the subset of traits can eventually become the normal phenotype.
The following is multiple choice question (with options) to answer.
A skunk wards off predators with | [
"a noxious spray",
"bad taste",
"a powerful nose",
"smelling good"
] | A | most animals avoid bad odors |
OpenBookQA | OpenBookQA-2162 | terminology, meteorology
I've tried to illustrate the relationships with insolation and temperature here:
There are some other ways too:
Ecological. Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, sometimes using 6 seasons in temperature zones, or only 2 in polar and tropical ones.
Agricultural. This would centre around the growing season and therefore, in North America and Europe at least, around frost.
Cultural. What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). Here's another example of a 6-season system, and a 3-season system, from the Aboriginal people of Australia, all based on weather.
Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the seasonal lag means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no heat capacity, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:
The exact same effect happens on a diurnal (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.
These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.
The following is multiple choice question (with options) to answer.
Needing to predict planting and harvesting times and when certain food animals would hibernate, early humans learned repeating weather patterns, star formations and time intervals to realize that | [
"the sky is usually blue at night",
"most plants take a year to grow",
"one year consists of 365 days and nights",
"the sun is still for 12 months a year"
] | C | one year is equal to 365 days |
OpenBookQA | OpenBookQA-2163 | photosynthesis, botany
Title: Photosynthesis - Light Intensity Say I was conducting an experiment for photosynthesis. If I moved light closer to the plant, what effect would this have on the process of photosynthesis? The rate of photosynthesis varies from plant to plant. Some plants require more light and some require less. If you move light closer to the plant, in most scenarios the rate of photosynthesis is likely to be increased. For some plants a minimal light is enough for their photosynthesis, so for those plants, moving light source closer or further will have less effect.
The following is multiple choice question (with options) to answer.
A plant needing to photosynthesize will want to be placed nearest to a | [
"fridge",
"bed",
"skylight",
"basement"
] | C | a plant requires sunlight for photosynthesis |
OpenBookQA | OpenBookQA-2164 | javascript, beginner, jquery, html, adventure-game
<div class="situation_text">
You walk away from the cave, to search for food. You find berries. Do you eat them or not?
</div>
<input type="button" class="situation_choice"
value="Eat the berries"
data-situation-target="eat_berries">
<input type="button" class="situation_choice"
value="Don't eat the berries"
data-situation-target="ignore_berries">
</div>
<div class="situation" data-situation="eat_berries">
<div class="situation_text">
You eat the berries.
</div>
</div>
<div class="situation" data-situation="ignore_berries">
<div class="situation_text">
You ignore the berries. You are still hungry.
</div>
</div>
</html>
The following is multiple choice question (with options) to answer.
A girl wants to enjoy some fresh strawberries. She checks the patch in the garden where strawberries grow, but still a ways away from being ready, because they are still | [
"bees",
"buds",
"dirt",
"trees"
] | B | plants are the source of fruit |
OpenBookQA | OpenBookQA-2165 | astronomy, everyday-life, popular-science, climate-science
Title: Why is the summer, in the temperate latitudes, in average, hotter that the spring? It is common knowledge that the transition from the Spring to the Summer season occurs in the Summer Solstice when the "Sun reaches its highest excursion relative to the celestial equator on the celestial sphere" (as stated in Wikipedia).
It is also stated in Wikipedia' Summer page:
"Days continue to lengthen from equinox to solstice and summer days progressively shorten after the solstice, so meteorological summer encompasses the build-up to the longest day and a diminishing thereafter, with summer having many more hours of daylight than spring."
My question is: why is the summer, in the temperate latitudes, in average, hotter that the spring? A major part of the reason for this is due to the temperature of the ground. While the length of days in the Summer are effectively a mirror of those in Spring, you must take into consideration more than that.
When Spring commences in temperate climates, it is (usually) immediately preceded by winter. Due to the Winter, the ground and/or surrounding bodies of water are very cold. This has the effect of cooling the air for the first part of Spring while the ground/water begins to thaw/warm up. Furthermore, it takes much longer to warm or cool a body of water than a mass of air; even longer to warm or cool the ground and water. Therefore, as Spring progresses and the days become longer (also meaning the Sun is higher above the horizon, thus providing more heating power), the sunlight must first overcome the cooling effects of the ground and water bodies. Near the end of Spring - when the days are sufficiently long and the Sun is much higher above the horizon - you should notice the weather becoming hotter. This is because the ground and water has had time to warm up, which means it is not constantly cooling the air and making it feel colder.
When you then transition to Summer, the ground is already sufficiently warm but the days are still long and the Sun is still high in the sky. This means the Sun can heat the ground, water, and air even more and without any cooling effects. This allows the Summer temperature to be easily higher than that of the Spring temperatures. If Summer were immediately preceded by winter, you might notice the weather getting warmer much more quickly, but the average temperature would be very close to that of the Spring.
The following is multiple choice question (with options) to answer.
Opposite the winter solstice, the summer solstice features | [
"longer daylight",
"less daylight",
"brighter fires",
"more darkness"
] | A | the amount of daylight is greatest on the summer solstice |
OpenBookQA | OpenBookQA-2166 | death, kidney
Title: For how long can a person drink sea water? How long could a person of lets say 18 years be able to drink sea water without getting too much into trouble ? Or can a person drink it without noticing that it is a very bad idea ? I don't mean in just 1 drink session but like can one manage a day or two ? Can one drink it and go to sleep and be still healthy (although very thirsty) in the morning ?
(this is just a hypothetical question, I'm not a scientist at all, I'm not sure what tags to use actually)
Additional brainstorming:
kidney failure
any other organ failure
dying of thirst
...
(source: free.fr)
Alain Bombard
He is a french biologist who voluntarily tested how many days a man can survive drinking seawater and how?
Biologist point of view
Sea contains ~3.5% of salt$^1$. Our kidney separates the waste from water and excrete them in urine provided the salt content is less than ~2%.$^2$
So, it will take the water already present in the body. Causing excessive thirst and dehydration, eventually cause death.
Alain's Experiment
Just one spoon of seawater at 20 minute intervals, drinking very
slowly and letting the saliva in your mouth reduce the saline in the
water you have swallowed.
Though he survived 65 days (From and including: Sunday, 19 October 1952
to Tuesday, 23 December 1952, ~4,400km) of his journey and lost 25 kg of weight, this result is never successfully reproduced.
Source:
http://oceanservice.noaa.gov/facts/whysalty.html
http://paradise.docastaway.com/drinking-sea-water
The following is multiple choice question (with options) to answer.
A person who forgot to bring water with them will likely die of dehydration | [
"on a lake",
"in a river",
"in a house",
"on earth's satellite"
] | D | the moon does not contain water |
OpenBookQA | OpenBookQA-2167 | ecology
I have tried to find explanatory texts both in this and other books without any success so my question is how's this balanced state achieved in both types of successions (the answer is hinted in the first paragraph which I don't quite understand)?
Related to my last post. The author is saying that 1) Mature ecosystems tend to have a balance between production (=P) and use (=R, respiration) of biomass. This is actually tautological because the author would probably define a mature ecosystem as one where this is true (P=R).
If it starts out P > R, the autotrophs are dominant: more biomass is being produced than used up. It is possible, for a time, that P will increase as, for example, plants grow more leaves, but R is growing too, and there is an eventual limit on P, which at maximum depends on the light available to the ecosystem. As biomass grows, so does the amount of biomass to potentially decay, so eventually R will always catch up to P, until there is balance.
If it starts out P < R, that means you are using up biomass faster than you are creating it. This case is even simpler: you will gradually run out of biomass, and R will decrease.
In either case, when the author is talking about P = R, this is going to be in relative terms; there might still be variations between them, for example seasonal variation, but on average over years or decades you would expect P = R in a mature, stable ecosystem.
The following is multiple choice question (with options) to answer.
Which of the following is an example of ecological succession? | [
"a group of horses slowly becomes extinct due to loss of habitat",
"a group of rats in a lab learn to navigate a maze",
"a soccer team trains for the championship",
"Trees, insects, and birds in a forest grew from wildfire-ravaged lands"
] | D | ecological succession means entire communities in an ecosystem change over time |
OpenBookQA | OpenBookQA-2168 | visible-light, electromagnetic-radiation, speed-of-light, everyday-life, atmospheric-science
If the blocking occurred close to the sun, you would see the opening of the blocking ca. 8 minutes after it happened, but you would also feel it 8 min after it happened. Thus you would experience both at the same time.
An analogy:
Imagine a car standing at a tunnel entrance that is blocked. You are standing at the opposite end of the tunnel. Now the road is opened and the car drives through the tunnel towards you. The car reaches you ("warmth") at the same moment that you receive the information that the tunnel is not blocked anymore. It does not matter how long the tunnel is or how fast the car is driving.
The following is multiple choice question (with options) to answer.
Within a twenty four hour period, a person could experience | [
"a globe's complete rotation",
"thirty hours of night",
"a day on Pluto",
"a year of schooling"
] | A | one day is equal to 24 hours |
OpenBookQA | OpenBookQA-2169 | waves, pressure, acoustics, air
Title: How can sound waves propagate through air? We know that the sound waves propagate through air, and it can't travel through vacuum. so the thing that help it doing that is the air's molecules pressure. So my question how can that happens? I can't understand that concept. Sound waves propagate very similarly to how 'the wave' propagates at baseball stadiums:
http://www.youtube.com/watch?v=H0K2dvB-7WY
At some point something (your vocal cords, a piano string, a speaker) hit a bunch of air particles (atoms, molecules, it really doesn't matter). These particles in turn hit the particles next to them, these hit the ones next to them and so on. No pressure here is simply the absence of any particles, so nothing communicates the orders to move. This is like ' the wave' in that everyone communicates the motion of the wave of the person standing next to them, and if there is no one standing next to you, the wave ends with you. Hearing a sound is the last bunch of air particles next to your ear drum getting the instructions to vibrate which in turn vibrates your ear drum and your brain turns this response into the perception of sound.
The following is multiple choice question (with options) to answer.
Sounds may travel through air where there is an atmosphere. Sounds that can travel include | [
"honking",
"listening",
"thinking",
"sweating"
] | A | sound can travel through air |
OpenBookQA | OpenBookQA-2170 | newtonian-mechanics, energy-conservation, rotational-dynamics
Title: Ball rolling on half-pipe It is well-known that a ball rolling down a half-pipe where the side it starts on has enough friction for the ball to roll without slipping and on the side other to be frictionless, that the ball will not roll to as high of a position on the other side as it started because at its maximum it still has rotational energy that it didn't have at the beginning which means that not all of its kinetic energy could have been converted back to potential energy. See the picture below:
The following is multiple choice question (with options) to answer.
A person can create the most friction by rolling a ball over | [
"glass",
"gravel",
"ice",
"marble"
] | B | as the roughness of something increases , the friction of that something will increase when its surface moves against another surface |
OpenBookQA | OpenBookQA-2171 | immunology, virology
Title: Why do people dying of immune deficiency diseases appear sick? Please forgive the obviously silly appearance of this question, and/or of the tenor which may come across as flippant or dismissive of real world suffering. My intention is none of the above.
As a layperson, I have always understood that the expression of our various colds/flus etc, while frequently mis-understood as being caused by the virus, are actually just manifestations of our own immunity fighting same. In other words, all the snot, and fever and inflammation are not caused *by the virus, they are a reaction *to the virus, as we fight it off.
My question then is why do people with AIDS (or similar immunity destroying affliction) appear sick? If they have weak or non-existent immune systems, following the above logic, would one expect to see them passing away while looking entirely healthy? Many of the symptoms of disease are indeed related to inflammation, but inflammation depends heavily (though not solely) on the innate immune response. Patients with AIDS and some of the other immunodeficiencies lose their adaptive immune response, not their innate response. Therefore they are capable of mounting an inflammatory response that is not effective in clearing pathogens (because it doesn't have help from the adaptive immune system) but can still cause symptoms.
More importantly, many symptoms of disease are not caused by the inflammatory response, but are related to organ and tissue damage caused by the infection. A patient with pneumonia may have a reduced inflammatory response but will still have difficulty breathing and signs of reduced oxygen supply simply because the lung tissue has been damaged by the pathogen.
The following is multiple choice question (with options) to answer.
Which of the following would be a reason you are sick? | [
"a cut on your thumb allowed bacteria inside",
"your hair follicles get dirt on them",
"your stomach digested a delicious breakfast",
"your nose allowed water inside"
] | A | skin is used for protecting the body from harmful substances |
OpenBookQA | OpenBookQA-2172 | star, planet, telescope, light, space
Title: How do I know what I'll be able to see? So I live in a suburb in Victoria, Australia. Less than an hour away from the city and I guess there is a bit of light pollution because from my backyard I can probably only see about 15 - 20 stars (probably less), I'm wondering what these stars are, and what I'll see when I get this telescope:
https://www.opticscentral.com.au/saxon-707az2-refractor-telescope.html?___SID=U#.WXQNMtN940r
This is going to sound stupid but how do I know when there are planets in the sky that I can see? I don't think I've ever actually seen a planet other than the moon.
Thank you. Firstly, if you're planet spotting, don't worry too much about light pollution. The planets are some of the brightest objects in the sky and some (especially Jupiter) can easily be observed even with a full Moon - the full Moon (along with the Sun!) is the biggest contributor to light pollution!
Take a look at the list of brightest stars ( https://en.wikipedia.org/wiki/List_of_brightest_stars ), which also contains estimates for the brightness of the Sun, Moon and major planets. There aren't typically any stars brighter from Earth than Venus, Jupiter, Mars and Mercury and precious few brighter than Saturn. I'm going to suggest you probably have seen many of the planets - but just didn't recognise them.
+1 for Stellarium ( http://www.stellarium.org/en_GB/ ). It's free, intuitive and very visual to use. You can put in your local viewing location and it gives you a view for any time of the night, future or past. At the time of writing (23 July 2017), Saturn and Jupiter should be looking good for the Southern Hemisphere. This rotates throughout the year, and Stellarium will help with this.
Do a web search for "the sky at night in the southern hemisphere" and you'll find a number of examples of websites with highlights to look for when you get out.
Couple of final suggestions:
The following is multiple choice question (with options) to answer.
At nighttime, which are you most likely to see? | [
"changing views of the horizon",
"changing views of the Sun",
"changing views of mountains",
"the big Dipper disappearing over the horizon"
] | D | stars appear to move relative to the horizon during the night |
OpenBookQA | OpenBookQA-2173 | species-identification, zoology, bone-biology, bone
Title: What is this bone from? This object showed up on my fire escape in New York city. It appears to be some kind of bone. It's a bit smaller than an adult human hand. What animal is it from? Given the size and thin/elongated ilia as well as the urban location, I think a domestic cat and/or a raccoon are likely candidates. I'm leaning toward cat.
Cat pelvis:
VCA Hospitals
Ventral view of domestic cat pelvis; Source: BoneID
Raccoon Pelvis
Anterior view of raccoon pelvis; Source: BoneID
I'm not an expert in differentiating these two species' bones. I will note that your specimen is more or less in between the sizes of these two species. Your size is probably closer to the raccoon, but a cat is just more likely given the location.
The most noticeable trait that stands out to me is the size/pointedness of the ischial tuberosity, which better matches that of the cat.
The following is multiple choice question (with options) to answer.
Which of the following animals would be most likely to be in disguise? | [
"a chameleon",
"a dog",
"a bird",
"a cat"
] | A | disguise means change appearance to hide |
OpenBookQA | OpenBookQA-2174 | experimental-physics, water, fluid-statics
Title: Determine water level difference in two ponds I live near two ponds whose water levels appear to differ by a few feet. The ground is hard clay, so I don't think there's any underground water exchange between the ponds. The ponds are separated by about 30 feet of a bumpy terrain, with the bumps reaching a few feet above the "higher" water level. What is the cleverest way to determine the difference in water levels between these ponds? What comes to mind is to stick two poles (several feet high) at the water line in each pond, stretch a string between them, level the string with a bubble level and measure the distances between the string and the water level on each pole. Any other ideas? Fill a garden hose with water. Hold both ends closed, and walk to the "higher" pond. Have someone helping you hold the end of the hose under water.
Now walk to the other pond (still holding the end of the hose shut). Hold the hose near the surface of the pond - you should feel water pressing against your finger. Make a very small opening and observe the water coming out.
Now raise the hose slowly. At the point where the water stops flowing, the end of your hose is at the level of the higher pond.
Measuring the height difference is now trivial.
Incidentally - you mentioned that the ground between the two ponds was "bumpy". This raises the question of whether this bumpiness affects the result.
What we have here is a siphon: if the water is not flowing, the pressure at any point along the hose is simply given by the height of the point relative to the level of the body of water that the inlet of the hose is submerged in. In fact, the pressure will be
$$p = p_0 - \rho g h$$
Where $\rho$ is the density of water (usually 1000 kg/m3), $g$ is the gravitational acceleration (9.8 m/s2) and $h$ is the height above the pond level. As you can see, when $h$ becomes greater than 10 m the pressure will become negative: this means the water will boil (evaporate), creating a bubble in the hose. At that point, the relationship is no longer simple. On the other hand, if the hose goes through a valley, the local pressure will be higher - but this will not matter in the end.
The following is multiple choice question (with options) to answer.
The volume of water in a pond could increase if | [
"the water drains out of the pond",
"a large flock of ducks visits the pond",
"people swim in the pond",
"there is stormy weather"
] | D | storms cause bodies of water to increase amount of water they contain |
OpenBookQA | OpenBookQA-2175 | reaction-mechanism, redox, hydrogen
The resulting oxygen radicals can again react with $\ce{H2}$ to form more hydrogen radicals. This reaction is also endothermic.
$$\ce{O + H2 -> HO. + H.}$$
The hydroxyl radicals can also react with $\ce{H2}$ to form more hydrogen radicals, which is a slightly exothermic (releases energy) reaction.
The net result of those equations leads to a slightly exothermic sum, with high potential:
$$\ce{3H2 + O2 -> 2H2O + 2H.}$$
In principle, the hydrogen radicals react as a catalyst. However, this reaction is a highly branched chain reaction, including a lot of radical reactions. Due to this, more and more hydrogen radicals will be produced.
This scheme will eventually end when the concentrations of $\ce{O2,H2}$ will become lower forcing the excess radicals to react with each other.
$$\ce{HO. + H. -> H2O}$$
Another possibility is forming as a byproduct hydrogen peroxide, which is a very exothermic reaction:
$$\ce{H. + O2 -> HO2.}\\
\ce{2HO2. -> H2O2 +O2}$$
(Also happening but not as important: $\ce{HO. + HO. <=> H2O2}$)
As long as there are hydroxyl and hydrogen radicals present, the peroxide will take part in the chain reaction. However, this reaction also provides the necessary energy to cleave more $\ce{H2}$. peroxide is also easily cleaved again, or reacts with each other:
$$\ce{2H2O2 -> 2H2O + O2}$$
This all results in the main product water.
Please keep in mind, that there are many factors, that influence these reactions. It is strongly dependent on pressure, temperature, and surroundings. Surfaces and/ or catalysts involved in this reaction may change it completely.
The following is multiple choice question (with options) to answer.
A person can cause a chemical reaction by adding heat to | [
"a rock",
"a diamond",
"cake batter",
"a wall"
] | C | adding heat to an object sometimes causes chemical reactions |
OpenBookQA | OpenBookQA-2176 | beginner, tree, rust
}
impl <T : Clone> BTree<T> {
fn mirror(&self) -> BTree<T> {
match *self {
BTree::Leaf(_) => (*self).clone(),
BTree::Branch(ref l, ref r) =>
BTree::Branch(Box::new((*r).mirror()), Box::new((*l).mirror())),
//
// why does this work?
// BTree::Branch(Box::new(r.mirror()), Box::new(l.mirror())),
}
}
}
#[test]
#[allow(unused_variables)]
fn test_btree_creation() {
use BTree::*;
let leaf: BTree<i32> = Leaf(10);
let branch: BTree<i32> = Branch(Box::new(Leaf(15)), Box::new(Leaf(20)));
let tree: BTree<i32> = Branch(Box::new(branch.clone()), Box::new(Leaf(30)));
assert_eq!(branch, branch.clone());
}
#[test]
fn test_btree_depth() {
use BTree::*;
assert_eq!(Leaf(10).depth(), 1);
let branch: BTree<i32> = Branch(Box::new(Leaf(15)), Box::new(Leaf(20)));
assert_eq!(branch.depth(), 2);
let tree: BTree<i32> = Branch(Box::new(branch.clone()), Box::new(Leaf(30)));
assert_eq!(tree.depth(), 3);
let other_tree: BTree<i32> = Branch(
Box::new(branch.clone()), Box::new(branch.clone()));
assert_eq!(other_tree.depth(), 3);
}
The following is multiple choice question (with options) to answer.
If a tree is going to give its essence to another tree, it needs to use | [
"small creatures",
"great stamina",
"positive attitude",
"mighty strength"
] | A | pollination requires pollinating animals |
OpenBookQA | OpenBookQA-2177 | telescope, optics
Title: Shouldn't this cause a fire? This website shows a telescope projecting the sun onto a blackboard: https://astronomyconnect.com/forums/articles/2-three-ways-to-safely-observe-the-sun.21/
Why isn't the board catching fire? You can easily start a fire on a sunny day by targeting the focal point of a magnifying glass onto something flammable. Why isn't the telescope in this picture doing the same thing?
Photo by Luis Fernández García It could start a fire if the screen is at the focal point of the optical system. That is how you light fires with a magnifying glass.
Here, the blackboard is likely away from the focal point, so you can see the shape of the eclipse (and you get a bigger image) without setting things on fire.
Although this is fairly safe, there are a few things to pay attention to:
If you do this, make sure nobody can walk between the telescope and the screen, because if they go near the focal point, they could get very hot.
Doing this will cause your telescope to heat up. If there are any plastic parts, they can melt.
The telescope in the picture seems to have a small opening. Don't do this with a big telescope. You don't need to collect a lot of light.
Not an answer to the question, but an important note: Observing the Sun is the most hazardous thing you can do in astronomy. Make sure you know what you are doing before you try.
The following is multiple choice question (with options) to answer.
A horse barn fire | [
"damages only the pastures",
"would be easy to handle",
"damages the structure and animals trapped inside",
"would cause very few issues"
] | C | burning a living thing usually causes harm to that living thing |
OpenBookQA | OpenBookQA-2178 | thermodynamics, radiation, laser, thermal-radiation, heat-engine
Title: Most efficient mechanism for heating air I was read about small scale ion treatment which uses heats to high temperatures, would this be scalable and if so would there be any more efficient methods.
In summary, if you wanted to heat large volumes of air to 1000 celcius with only electricity what would be the most efficient method?
Would it be a laser and if so what frequency or would a superheated coil be best etc. The air is from between 25000 and 35000 ft of altitude, which ever would be more efficient. As the comments have noted, any answer depends on the many missing details about what you are trying to accomplish and any constraints on what you can do or afford. Is a “large volume” 1 cubic cm or 10000 cubic metres? Is it a static volume of air or is it constantly being exchanged for new air? What are the specifications of the available electric power? Must the volume of air be empty, or can structures (e.g. heating elements) pass through it? Is the air enclosed in a container? Is the container insulated? How long do you need the air to be at 1000°C? …
Energy conversion efficiency is not the problem. A simple heating coil connected to a DC battery can have almost 100% efficiency in converting the energy of the battery into heat. The maximum average temperature reached by the air will depend on the balance between the rate at which the electric coil is heating the air and the rate at which the air is cooling at its boundary by conduction, air exchange, or radiation. You want to maximize the surface area over which air is in contact with the heater, e.g. using metallic fins or meshes.
Why do you specify electrical heating? Does the “air” have to be the standard mix of atmospheric gases? The easiest way to get a bunch of very hot gas is to burn a fuel, and this is why hot air balloons up use burners. A tank of propane will produce much more heat than the same weight in batteries. (You may want to look at https://electronics.stackexchange.com/questions/112312.) I assume, however, that your air is not contained in a balloon since 1000°C is above the ignition or melting temperature of the balloon fabrics or films that I can think of.
The following is multiple choice question (with options) to answer.
Which of the following would you use to most efficiently transport heat? | [
"empty water bottle",
"cotton T-Shirt",
"baseball cap",
"empty soda can"
] | D | a thermal energy conductor transfers heat from hotter objects to cooler objects |
OpenBookQA | OpenBookQA-2179 | radiation
You see similar things happening here. The metal rod at the top of the lamp acts as a capacitive ground - given the very high voltage, a tiny charge will flow from the tip of the filament to the rod. There is a small amount of gas in the tube which is ionized and gives rise to the light you see. The electrons eventually bombard the metal "anode" and produce Bremsstrahlung - note that without the metal, you were getting a glow and no reading on the Geiger counter. There is a similar demonstration online which is more convincing in its use of conventional materials, but which otherwise shows many of the same phenomena.
It is almost certainly very inefficient. Most of the energy in an X-ray tube is converted to heat as the electrons burrow too deeply into the tungsten target for their radiation to escape- apart from the fact that only the most violent deceleration produces X-rays with high enough energy to penetrate the bulb and be detected.
I noticed that when the "alpha window" was removed, the reading in your video went up. Since there was also a biscuit tin and glass bulb in the way I suspect there was a lot more low energy radiation generated than was detected. Good stuff for skin cancer.
The experiment as shown should not be repeated. Not only were the HV precautions extremely poor, but so were the radiation safety precautions. Please don't try this at home...
The following is multiple choice question (with options) to answer.
John was able to read at night even though the electricity had gone out. John was using | [
"a pepperoni and cheese pizza",
"a heavy maple desk",
"an item made from a petroleum product with a cord sticking out the top",
"an old step ladder"
] | C | a candle is a source of light when it is burned |
OpenBookQA | OpenBookQA-2180 | entomology
Title: What is the name of this tiny creature? It looks like a tiny piece of moving cotton? By chance, I saw this tiny insect on my bag a few days ago in Sydney. Am I the first person who has pinpointed this animal?! If not can you please let me know its name? From your image, it looks like it might be a woolly aphid. I just did a bit of cursory research, and it looks like they're often described as floating pieces of fluff, that seem to wander instead of directly heading somewhere. The fluff on their back is actually wax produced as a defense mechanism from predators and the like. I hope this is what you were looking for!
The following is multiple choice question (with options) to answer.
A person wanting to protect their crops from insects could | [
"plant in a greenhouse",
"plant in a garden",
"plant in a field",
"plant in a grove"
] | A | insects can have a negative impact on crops |
OpenBookQA | OpenBookQA-2181 | javascript, game, array
// use the index value outputs to calculate the next room 'down' the worldMap array
console.log('next room down: ' + worldMap.findNextRoom('down'));
currentMap = worldMap.findNextRoom('down');
console.log('new currentMap = ' + currentMap);
The following is multiple choice question (with options) to answer.
A person is reading a map and gets frustrated. The map ends up in a hundred scraps on the floor because the person | [
"drowned it",
"burned it",
"ripped it",
"forgot it"
] | C | tearing means changing a whole into pieces |
OpenBookQA | OpenBookQA-2182 | The first of these factors, $$P(n_i=k \mid n_{i-1} = k)$$ is the probability of not finding the next toy in meal $$i$$. This depends only on how many toys we have: if we have one toy, the probability of getting that same toy again is 1/4. If we have three toys, the probability of getting any of them again is 3/4.
The second factor, $$P(n_{i-1} = k)$$ can be computed recursively.
Similar reasoning applies to the other case where we do find toy $$k$$ in meal $$i$$. In the end, the probability of having $$k$$ toys after $$i$$ meals is
$\begin{array}{l} P(n_i=k) &= &P(n_i=k &\mid &n_{i-1}&=&k) &\times &P(n_{i-1}&=&k) \\ &+ &P(n_i=k &\mid &n_{i-1}&=&k-1) &\times &P(n_{i-1}&=&k-1). \end{array}$
If you read it carefully, you should be able to figure out the intuitive meaning of each factor. Given what we know about the conditional probabilities, we can also simplify the calculation a bit more.6 If you are confused about the 5-k numerator: Given that we have $$k-1$$ toys after meal $$i-1$$, the probability of finidng toy $$k$$ in this meal depends only on how many toys we are missing. if we are looking for the last toy, the probability of finding it is 1/4. One place it’s easy to slip here is that if we are looking for toy $$k$$, that means we are missing not just 4-k toys, but 4-(k-1) = 5-k toys.
The following is multiple choice question (with options) to answer.
Tiny pips may be found inside of this food that is a breakfast treat. | [
"grapefruit",
"flour",
"macaroni",
"ranch"
] | A | a berry contains seeds |
OpenBookQA | OpenBookQA-2183 | newtonian-mechanics, momentum, acceleration, collision
Title: A problem regarding a fiction Recently I watched a fictional(I guess) video: a man is crossing the road while a truck accelerates towards him and a superhero flashes and saves his life by taking him out of the road. He was very fast, therefore only a flash could be seen. It seems like a silly incident though. After some time the question that occurred in my mind was 'if this happened in reality, could that man survive?'
This is my reasoning:
If the man had to collide with the truck it would create serious damages and this has been explained scientifically in many topics such as energy transferred to the body, force emitted, and so on. Also, I found that the acceleration of the vehicle performs a lower impact on the pedestrian. Nevertheless, everyone knows that more harm is done by a vehicle that goes with $60 \;\text{km/h}$ than $5 \;\text{km/h}$ at a collision. But in this scenario, the speed of the hero is exaggeratedly high(Find the video below). The speed of the truck is negligible in comparison. Thus the impulse on the man is massive when the hero catches him. Can a person endure such a great impulse? I heard that such a great change in momentum will disturb fluids in the person's body and feels extremely uncomfortable. And also can a person tolerate that acceleration? Thus the ridiculous thought that came to my mind was that the damage will be minor when the person had to be hit by the vehicle than is carried by the hero.
This seems to be a silly problem, but I am asking whether this could happen in the real world.
EDIT: Look for video here:- https://youtu.be/KJqhR2YSUXw
The following is multiple choice question (with options) to answer.
Which would result in the most dangerous driving experience? | [
"light rain",
"low speed",
"distant thunder",
"heavy fog"
] | D | a decrease in visibility while driving can cause people to crash their car |
OpenBookQA | OpenBookQA-2184 | experimental-chemistry
Pouring the copper sulfate solution into the beaker resulted in a vigorous reaction and quite a bit of heat. I stirred the reaction mixture and let it go to completion. The magnet still stuck strongly to the bottom of the beaker, indicating that there was still substantial powdered iron remaining.
The mixture was decanted to another beaker, with some mostly useless filtering (no good filter paper at hand), and allowed to settle for about an hour. The copper particles produced in the reaction are very small and settle out very slowly. Some of the supernatant solution was transferred to a sample cell, illuminated from the left via an LED flashlight and photographed. This is shown in the next figure:
Despite the light scattering, the green color of the ferrous sulfate solution is evident. The photo will be updated after more particulate has settled out.
The following is multiple choice question (with options) to answer.
A person may find that iron attracts other items such as | [
"plastic toys",
"broken bottles",
"grass stains",
"wire braces"
] | D | metal is sometimes magnetic |
OpenBookQA | OpenBookQA-2185 | electricity
Title: Problems with a lithium battery I have a lithium battery that is separated from any device and is producing a whitish-gray smoke every time the wires move. Sometimes it makes hissing noises.
Is there a way to solve these problems? You probably want to drain its charge and put it into recycling. It's probably a fire hazard at this point, and the damage that a fire from it could cause will cost more than a new one.
The following is multiple choice question (with options) to answer.
Using your electronic that uses batteries for long periods of time makes them get very hot to the touch, which makes it a | [
"source of ice",
"source of candy",
"Source of wind",
"source of warmth"
] | D | a hot substance is a source of heat |
OpenBookQA | OpenBookQA-2186 | inorganic-chemistry, redox, transition-metals
Title: Fe with different charges Taken these reactions:
\begin{align}
\ce{2\overset{0}{Fe} + 3Cl2 &-> 2\overset{+3}{Fe}Cl3} \tag{1}\\
\ce{\overset{0}{Fe} + 2HCl &-> \overset{+2}{Fe}Cl2 + H2} \tag{2}
\end{align}
Why does $\ce{Fe}$ have +3 charge in the first example and +2 charge in the second? Iron exists in the +2 oxidation state (iron(II)), also called ferrous iron, as well as the +3 oxidation state (iron(III)), also called ferric iron. There are sever other oxidation states of iron that are not pertinent to your reactions.
In your first reaction, the strongly oxidizing $\ce{Cl}$2
oxidizes the neutral, metallic iron to it's highest stable oxidation
state, iron(III).
In your second reaction, $\ce{HCl}$ oxidizes iron to the lower stable
oxidation state, iron(II).
The following is multiple choice question (with options) to answer.
Two iron bars that are similarly charged will likely | [
"pull each other",
"touch each other",
"shove each other",
"grab each other"
] | C | magnetism can cause objects to repel each other |
OpenBookQA | OpenBookQA-2187 | thermodynamics, energy, power
Toyota Corolla, 13 gallon tank, 20% efficiency, 103 kWh usable energy
Tesla Roadster, 56 kWh battery capacity
Chevy Volt, 16 kWh battery capacity
If we compare a liquid Nitrogen car to the Chevy Volt it might not be so bad. But why would we do that? That car can still augment its range with gasoline. A part of the argument for electric cars is that you don't have the same energy loss from idling. Would that be true for a liquid Nitrogen car? There is no reason to believe that.
Let's say we assume a reasonable efficiency of half the isothermal process, which is illustrated in Figure 2 of the reference. Let's also say we'll hold 50 kWh of usable energy in the tank (even though this could still cause range problems). We've increased the tank size by a factor of 4 and the weight of the full tank is now around $1000 kg$. This is close to what many cars weigh.
The energy content relative to gasoline, as well as the alternatives, kills the idea. It would seem to require extremely optimistic assumptions to make it a reasonable proposal before we even get into the discussion about infrastructure needed to make it happen. The most fair comparison would be to other cars that also use alternative fuels, but it fails there too. EVs seem to have better viability on the basis of simple energetics. Maybe you're concerned that we'll run out of Lithium. A vehicle powered by compressed natural gas (not even the super-high pressure tanks that many have hope in) would blow it away, and the tank would be more manageable. Plus the fuel would be (dramatically) cheaper. Plus the infrastructure would be there. Plus, the engine is a proven design. We could do better with coal-to-liquids, we could probably do better with biofuels.
The following is multiple choice question (with options) to answer.
An electric car will have difficulty receiving energy at | [
"a power outlet",
"an electric station",
"a charging station",
"a gasoline station"
] | D | an electric car contains an electric motor |
OpenBookQA | OpenBookQA-2188 | magnetic-fields, earth
Title: Would a compass on its side point at the ground? From a point just north of the equator, A straight line to the Magnetic North would be through the earth. If a compass was turned on it's side, would the north pointing arrow point toward the ground along that straight line? A compass is usually used to find the direction of the horizontal magnetic field of Earth at that point. The needle of a compass is very light and thus its efficiency decreases when the compass is not in the horizontal plane at that point (due to gravity).Therefore, where the compass would point will become unpredictable. But, yes, in ideal conditions, the compass would point along the straight line joining that point to the north pole.
The following is multiple choice question (with options) to answer.
A needle lined with magnets will pull north. If north is to the right and you want to go west, you'd walk | [
"straight",
"left",
"backwards",
"right"
] | A | when the needle of a compass lines up with Earth 's magnetic poles , the needle points north |
OpenBookQA | OpenBookQA-2189 | physical-chemistry, everyday-chemistry, pressure, capillary-forces
Another way to think about it is this: as each microscopic parcel of liquid wicks into the unsnapped bud, it leaves a region of slightly lower pressure behind it. Since the end of the liquid column facing the snapped bud is open to atmosphere, that results in a pressure differential against the snapped-bud side of the liquid column that pushes the liquid up toward the unsnapped bud.
The following is multiple choice question (with options) to answer.
When liquid that was sucked out of the ground by flora moves is moved to the air this is called | [
"perspiration",
"hydration",
"condensation",
"transpiration"
] | D | transpiration is when water vapor moves from leaves into the atmosphere |
OpenBookQA | OpenBookQA-2190 | agriculture
Title: What does "permanent field" mean in agriculture? I am reading a book that in a paragraph talks about the agricultural methods used in prehistoric Finland.
The further north and east, the more extensive the amount of
burn-beat cultivation, which was a far from primitive form of
agriculture. The yield was many times higher (twenty- to thirty-fold)
than on permanent fields (five- to ten-fold), and there were multiple
varieties of the technique
A history of Finland by Henrik Meinander.
One of them is burn-beating. Like I understand, in burn-beating people cut down the trees in the forests and burn the topsoil. This way they can use that soil for 3 to 6 years for cultivation.
The other method is permanent field. I have searched the internet and the result I got was "permanent crops", like here. In which case people planted trees once in a field and harvested them multiple times.
But in another research about prehistoric Finland it was saying:
The site of Orijärvi shows that permanent field cultivation, with
hulled barley as the main crop was conducted from approximately cal AD 600 onwards.
The following is multiple choice question (with options) to answer.
The field a farmer plants with varied crops over the years is richer than | [
"a field where apples, beans and squash is planted",
"a field where only grain is planted",
"a field where rice, corn and beans are planted",
"a field where fruits and vegetables are planted"
] | B | crop rotation has a positive impact on soil quality |
OpenBookQA | OpenBookQA-2191 | safety, equipment
Finally, make sure someone doesn't get the idea that the hood will stop all fumes and try to do a perchloric acid experiment using that hood--that will go badly.
Now, all this being said...
What you really need isn't to make this safe, what you need is to convince administration that you're doing things safely. This may have nothing at all to do with whether things are actually safe or not.
At my old school (where I was briefly president of the local ACS chapter), I could have put an experiment into a fume hood with no filter, not plugged the thing in, and gotten an okay from the administrators because they believed that fume hood = safe and no fume hood = unsafe no matter what else was going on.
I say this not to encourage you to try to trick your way out of this, but to point out that, unless your administration is scientific (i.e. actually understands science), then it's fairly likely you're going to have to jump through a few silly hoops in order to satisfy them.
Best of luck!
The following is multiple choice question (with options) to answer.
What can an individual do to REDUCE their pollution levels? | [
"buy and sell bikes to commuters",
"go on a biking tour of the country",
"go on a biking tour of the city",
"replace their driving to work with biking"
] | D | riding a bike does not cause pollution |
OpenBookQA | OpenBookQA-2192 | geophysics, sedimentology
Title: Does dirt compact itself over time? If so, how does this happen? If I were to bury something 10 feet (~3 metres) underground, with loose soil on top, would the ground naturally compact itself over time, until whatever I had buried has dirt tightly pressing against it on all sides?
What if I buried it 50 feet (~15 metres) underground?
If it exists, what is this compaction process called and how does it happen? Soil is a collection of various sized minerals grains, of various types of minerals produced by the weathering of rock. Typical soil minerals are clays, silts and sands.
The properties and behavior of different soil types depends of the composition of the soil: the proportion of clays, silts and sand in a soil. Sandy soils are well draining and clayey soils are sticky.
Between the grains of minerals that comprise a soil are spaces, called pores or pore spaces. The pores can be filled with either water or air, depending the location of water tables and wetting events like rain, snow melts or other forms of water inundation.
The density of a soil is dependent on the degree of compaction of the soil. For to a soil to be compacted, a stress has to be applied to the soil to realign the grains of soil which reduces the total volume of the pores and reduces the amount of air within the pores.
Consolidation of a soil occurs when pore space is reduced and water in a soil is displaced due to an applied stress.
Regarding having something buried and soil compacting around it over time, yes that will occur but it is a question of how much stress the soil experiences, the duration of time and the nature of the soil - sandy or clayey. Something buried for a day without any stresses not much will happen. But, something buried for thousands of years with people and animals walking over it, rain falling on the soil, vibrations from nearby human activity and an occasional earthquake all add to the stresses the soil will experience and increases the degree of compaction or consolidation over time.
The following is multiple choice question (with options) to answer.
An area of dirt contains large amounts of talc. That means that talc is able to be found in | [
"strawberries that grow elsewhere",
"strawberries that grow there",
"shark's stomachs under water",
"underwater caves in France"
] | B | if some nutrients are in the soil then those nutrients are in the food chain |
OpenBookQA | OpenBookQA-2193 | # Distribute 11 fish to 4 persons, where each person should have at least 1 fish and the fishes are not all identical
I have a problem that I have not been able to find a solution to:
There are 9 black fishes, 1 yellow fish and 1 blue fish that are to be given to four (distinct) persons. Each person should have at least one fish. In how many ways can this be done?
• You asked this question before at math.stackexchange.com/questions/541805/…. It's best not to have duplicates, so could you delete one of them? – user21820 Feb 6 '14 at 10:55
• @user21820. It is not exactly the same : objects became fishes ! Cheers. – Claude Leibovici Feb 6 '14 at 11:23
• @ClaudeLeibovici: If that is sufficient to make them different, then next month we will see fishes become sweets and... – user21820 Feb 6 '14 at 11:26
• @user21820. I was just kidding ! I just cannot believe that OP's can do that. Cheers. – Claude Leibovici Feb 6 '14 at 11:28
• @ClaudeLeibovici: Haha! It's hard to tell whether people online are joking! – user21820 Feb 6 '14 at 11:29
## 2 Answers
In special cases such as this, you can find specific properties to split cases. Here the most "constrictive" is the red and yellow objects, and either they both go to one person, or they to different people. In the first case, there are 4 ways to assign the red and yellow objects, and you need to use 3 blue objects to satisfy the other 3 people, and the other 6 can be distributed in any of $\binom{6+3}{3}$ ways (place 3 dividers between 6 objects). In the second case, there are $4 \times 3$ ways to assign the red and yellow objects, and you need 2 blue objects to satisfy the other 2 people, and the remaining 7 can be distributed in any of $\binom{7+3}{3}$ ways.
The following is multiple choice question (with options) to answer.
A person uses all of a renewable resource that they had in a bucket. They can get more of it by | [
"putting on fresh clothing",
"visiting a desert area",
"burning the bucket in a fire",
"leaving the bucket out in a storm"
] | D | a renewable resource can be replaced |
OpenBookQA | OpenBookQA-2194 | neuroscience, neurophysiology, memory, cognition
Title: What are the advantages of forgetting? How forgetting things is helpful for the brain or the human body biologically? This web page
After some moment of being rude, selfish, or weak, either we are able to put it behind us, or the person who suffered at the result of our imperfection moves on. The reason for this is our ability to forget about it. We forget not because we have an imperfect hippocampus (our brain’s memory organ); it's actually an evolved solution. The ability to lose information allows new information to come in that is more relevant, more pertinent to an ongoing reality. Forgetting allows us to update.
and this Huffington post article
According to a study in Nature, our awareness is limited to only three or four objects at any given time. To be able to think at your highest level, you therefore must be very efficient at filtering out all of the background noise: Your racing thoughts, the ringing phone, your neighbor’s barking dog, and the list goes on.
The Nature study found that when participants were asked to “hold in mind” certain objects while ignoring others, there are significant variations in how well each of us can keep irrelevant objects out of our awareness.
The researchers concluded that our memory capacity is therefore not simply about storage space, but rather “how efficiently irrelevant information is excluded from using up vital storage capacity.”
provide some backgrounds. Short answer
It has been shown that loss of long-term memories may enhance the retrieval of others. Short-term working memory is explicitly designed to be volatile and non-lasting. However, there are many other types of memories where memory loss may not be explicitly beneficial, or even outright debilitating such as in the case of Alzheimer's or stroke.
Background
First off all, there are many types of memories, including sensory memory, motor memory, short-term (working) memory, long-term memory, explicit & implicit memory, declarative & procedural memory and so on. Hence, because the question is quite broad, I will focus on long-term memory, short term-memory and sensory memory to discuss that memory loss can be beneficial, neutral, or detrimental.
The following is multiple choice question (with options) to answer.
What would be a benefit of skipping showers? | [
"getting facial acne",
"being smelly",
"having dirty hair",
"fostering healthy bacteria"
] | D | good bacteria grow on a human 's skin |
OpenBookQA | OpenBookQA-2195 | thermodynamics, energy, power
Toyota Corolla, 13 gallon tank, 20% efficiency, 103 kWh usable energy
Tesla Roadster, 56 kWh battery capacity
Chevy Volt, 16 kWh battery capacity
If we compare a liquid Nitrogen car to the Chevy Volt it might not be so bad. But why would we do that? That car can still augment its range with gasoline. A part of the argument for electric cars is that you don't have the same energy loss from idling. Would that be true for a liquid Nitrogen car? There is no reason to believe that.
Let's say we assume a reasonable efficiency of half the isothermal process, which is illustrated in Figure 2 of the reference. Let's also say we'll hold 50 kWh of usable energy in the tank (even though this could still cause range problems). We've increased the tank size by a factor of 4 and the weight of the full tank is now around $1000 kg$. This is close to what many cars weigh.
The energy content relative to gasoline, as well as the alternatives, kills the idea. It would seem to require extremely optimistic assumptions to make it a reasonable proposal before we even get into the discussion about infrastructure needed to make it happen. The most fair comparison would be to other cars that also use alternative fuels, but it fails there too. EVs seem to have better viability on the basis of simple energetics. Maybe you're concerned that we'll run out of Lithium. A vehicle powered by compressed natural gas (not even the super-high pressure tanks that many have hope in) would blow it away, and the tank would be more manageable. Plus the fuel would be (dramatically) cheaper. Plus the infrastructure would be there. Plus, the engine is a proven design. We could do better with coal-to-liquids, we could probably do better with biofuels.
The following is multiple choice question (with options) to answer.
Which vehicle would make less pollution? | [
"semi truck",
"Tesla Model S",
"Ford Explorer",
"Toyota Tundra"
] | B | electricity causes less pollution than gasoline |
OpenBookQA | OpenBookQA-2196 | meteorology, severe-weather
The lack of rich low-level moisture is due in large part to the lack of accessibility from warmer moisture sources, particularly the Gulf of Mexico; the Rockies provide a barrier to much of the moisture reaching further west.
As you note, parts of Wyoming and Montana do see supercells and tornadoes a bit more often... but on a good topographic map, fair parts of those states are east of the Continental Divide, and so still on an "upsloping" area and thereby not blocked by sinking regions which prevent full moisture progress. They're still less-tornado prone due to elevation and increased distance from moisture, but it does happen.
The desert southwest also does manage to get monsoon moisture sneaking around the terrain further south... but further north that monsoon moisture sees additional blocking by the more elevated terrain across Nevada and Utah. (And in the southwest, a different key ingredient in tornadic supercell development is typically missing in the summer monsoon: upper-air winds sufficient for supercell development)
The Pacific Coast does see a few occasional tornadoes. But from what I've seen, they typically form from smaller storms with much less classical and intense mesocyclones. As you mention, they're a bit more in line with cold-core setups, which usually produce weaker short-lived tornadoes than classic supercells of the Plains and on east. If you plug in the events you speak of into SPCs Severe Weather Events archive, [pick the date, then click Obs and Mesoanalysis on the left, then use the dropdowns to find various parameters]
you can see that CAPE was typically very meager (well short of 1000 J/kg) and the storm structure quite weak in reflectivity in comparison to a classic supercell, more indicative of such cold-core setups.
Capping inversions may be helpful to "keep the lid on the pot" if you have strong CAPE (and therefore quality moisture) and intense updrafts to erode the cap during the day. But as it is, there isn't enough moisture typically for the cap to be a positive factor.
The following is multiple choice question (with options) to answer.
Which state would receive the least amount of rainfall? | [
"Oregon",
"New York",
"Florida",
"Arizona"
] | D | a forest environment receives more rainfall than a desert |
OpenBookQA | OpenBookQA-2197 | energy-efficiency, thermal-insulation
Assuming you have a window opening of about 1$[m^2]$, the savings are about 1.5 times greater that LED.
Obviously, the savings will be :
The following is multiple choice question (with options) to answer.
A person wanting to use the daylight to power objects would consider adding to their home a few | [
"absorbing converters",
"convertible socks",
"metal eaves",
"play streets"
] | A | a solar panel converts sunlight into electricity |
OpenBookQA | OpenBookQA-2198 | Suppose A and B are statements of interest. Suppose we want to say in a short sentence that “whenever A is true, B is true, and that when A is false, we do not claim anything about the truth of B”. We use the word “implies” and state for short that “A is true implies B is true”, and mean the truth relations in the truth table you wrote. For this truth table, it wouldn't be meaningful for a good definition of "implies" to have A is false, B is true, "implies" is true. This would mean we are stating that B is always true, which is a valid claim to make, but not very helpful for a suitable definition of "implies".
Keep in mind we could state a different claim, namely, that “whenever A is true, B is true, and whenever A is false, B is false”. Here we are interested in claiming something about the truth of B when A is false. In this case we use the relation “iff” for short. We use this relation make the brief statement: “A is true if and only if B is true” and mean a different set of truth relations. In particular, A is false, B is false, the relation “iff” is true. Further, A is false, B is true, "iff" is false.
Now when you substitute “real” phrases for A and for B, you have to understand clearly what you are stating. Let’s say A is “Sticking a fork in an electrical outlet” and B is “you will get hurt”. Stating “A implies B” is the same as claiming that “if you stick a fork in an electrical outlet, you will get hurt”. This claim may not in reality be true, but that point is irrelevant to the statement from a logical point of view. The key point is that you are claiming nothing about getting hurt if you don’t stick a fork in the outlet. So in short, at this point it’s a matter of defining suitable definitions for useful relations, not about physical reality. Later of course we can do experiments, observe Nature, etc. to test if our claims hold up.
The following is multiple choice question (with options) to answer.
Which is likeliest to be true? | [
"octopuses are found in the jungle",
"birds are found in the deep ocean waters",
"sheep are found high in the tree",
"seaweed is found in the shallow waters near the beach"
] | D | aquatic plants live in bodies of water |
OpenBookQA | OpenBookQA-2199 | human-biology, neuroscience, zoology, physiology, history
If it is a mutation or set of mutations as the current thinking implies, there is a good chance that it is a combination of strong selection and accident. Its true that cooperation is often enjoys a strong selective advantage, but it doesn't make you smart or hospitable. When we talk in biology we don't say altruism, we say cooperation. If such cooperation happened only because of selection, we would see such behavior in other primates. So if we see this, I would lay odds to look for a rather complicated story...
Another interesting person to read is anthropologist Terrence Deacon, who is trying to understanding the terms with which we define intelligence. About ten years ago there were actually experiments that showed that chimpanzee some strong candidate intelligence genes related to cognition could be put into people (who needed gene therapy because they had lost cognitive function) and restore that function. Apologies, this is anecdotal - i saw him give a great talk, but he's moved on a bit and can't find the references.
This is important I think because the fundamental definitions of human intelligence have failed over the years, from the old chestnut of using tools, to a recognition of mortality, to awareness, animals have surprised us, particularly primates. I wonder whether we will be able to confirm these vital factors until we get a monkey asking for the keys to the car so that they can go get some pizza.
The following is multiple choice question (with options) to answer.
Many of our traits are unable to be naturally changeable, so we are stuck with them they way they are unless we opt for surgery. One of those traits is | [
"language",
"money",
"color",
"home"
] | C | the colors of the parts of an organism are inherited characteristics |
OpenBookQA | OpenBookQA-2200 | organic-chemistry
Title: What are the minimal chemical requirements for a food which we all can eat? I've been puzzled by the following though experiment for the past few days:
I want to make my own food from scratch, but I do not know where to start from.
I want to be 100% sure that what I eat will never contains something that can damage my body. For example: If you buy something from the local market you can not be 100% sure that it's safe to eat. (99.9 % maybe... but that's not 100%)
I want to ask you to tell me, how can I make a food that I can eat, or should I say - live on it, for the rest of my life, that's 100% safe, I can control every aspect of it's creation and has many combinations of taste because I love diversity.
Thank you for your time : )
Edit:
Because I realized my question is very broad and indeed is a little... too much scientific I want to close it. But before I do so, here's what I had in mind:
I wanted to take some chemical elements, put them in a jar, run some electricity, heat, whatever through it, filter it, do some additional processing and eat it.
I wanted to know if the stomach can take it, because I was going to eat food that's not hard to digest. Considering the three basic biomolecules used by the body are carbohydrates, lipids, and proteins, you would need to consume these three molecules only. Now we can choose three substances.
Glucose, one of the most basic carbohydrates, is needed for ATP production, so that would be a food choice there.
Any oil or butter will provide lipids.
Protein comes from a variety of sources. Meat is typically though of as the best, but nuts are a pretty good source too.
Since nuts satisfy proteins and lipids, I'd say honey roasted peanuts are the most basic food you could live off of, if you replace pure glucose for the honey.
The following is multiple choice question (with options) to answer.
What do you need to do to make food ready for human consumption? | [
"throw it into the ocean",
"stomp on it with your feet",
"create a chemical reaction using a stove",
"walk to a cemetary"
] | C | cooking causes a chemical reaction |
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