questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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Like a blanket on a sleeping person, greenhouse gases act as what for the planet?
Here are the choices:
A. insulation
B. Exterior Coverings
C. plastic
D. ventilation | Like a blanket on a sleeping person, greenhouse gases act as insulation for the planet. The warming of the atmosphere is because of insulation by greenhouse gases. Greenhouse gases are the component of the atmosphere that moderate Earth’s temperatures. | A: insulation. |
What is the process in which a solid changes directly to a gas without going through the liquid state called?
Here are the choices:
A. amplification
B. sublimation
C. vaporization
D. Diffusion | Sublimation is the process in which a solid changes directly to a gas without going through the liquid state. Solid carbon dioxide is an example of a substance that undergoes sublimation. | B: sublimation. |
How many forces do objects on earth have acting on them at all times?
Here are the choices:
A. four
B. three
C. ten
D. two | More than one force may act on an object at the same time. In fact, just about all objects on Earth have at least two forces acting on them at all times. One force is gravity, which pulls objects down toward the center of Earth. The other force is an upward force that may be provided by the ground or other surface. | D: two. |
How often does sperm develop in humans?
Here are the choices:
A. sporadically
B. rarely
C. continuously
D. monthly | C: continuously. | |
Scientists found that the youngest rocks on the seafloor were where?
Here are the choices:
A. mid-ocean ridges
B. mid - ocean sediments
C. trenches.
D. mid - ocean glaciers | The scientists used geologic dating techniques on seafloor rocks. They found that the youngest rocks on the seafloor were at the mid-ocean ridges. The rocks get older with distance from the ridge crest. The scientists were surprised to find that the oldest seafloor is less than 180 million years old. This may seem old,... | A: mid-ocean ridges. |
The reproductive tissues of male and female humans develop similarly in utero until a low level of the hormone testosterone is released from male what?
Here are the choices:
A. bladder
B. liver
C. gonads
D. kidneys | Human Reproductive Anatomy The reproductive tissues of male and female humans develop similarly in utero until a low level of the hormone testosterone is released from male gonads. Testosterone causes the undeveloped tissues to differentiate into male sexual organs. When testosterone is absent, the tissues develop into... | C: gonads. |
Flatworms have a concentration of nerve tissue in the head end, which was a major step in the evolution of what organ?
Here are the choices:
A. kidney
B. heart
C. brain
D. liver | Flatworms have a concentration of nerve tissue in the head end. This was a major step in the evolution of a brain. It was also needed for bilateral symmetry. | C: brain. |
What type of energy travels through matter in wave form?
Here are the choices:
A. magnetic
B. vibrational
C. sound
D. light | Sound is a form of energy that travels in waves through matter. The ability to sense sound energy and perceive sound is called hearing . The organ that we use to sense sound energy is the ear. Almost all the structures in the ear are needed for this purpose. Together, they gather sound waves, amplify the waves, and cha... | C: sound. |
What speeds up chemical reactions inside cells?
Here are the choices:
A. catalysts
B. nucleus
C. electrodes
D. inhibitors | Living things depend on catalysts to speed up many chemical reactions inside their cells. Catalysts in living things are called enzymes. Enzymes may be extremely effective. A reaction that takes a split second to occur with an enzyme might take billions of years without it!. | A: catalysts. |
What atmosphere do gills help exchange gas in?
Here are the choices:
A. water
B. stratosphere
C. ecosystem
D. air | A: water. | |
Community interactions are important factors in what?
Here are the choices:
A. natural process
B. natural selection
C. natural resources
D. natural change | A community is the biotic component of an ecosystem. It consists of the populations of all the species that live in the same area. Populations in communities often interact with each other. Community interactions are important factors in natural selection. They help shape the evolution of the interacting species. Types... | B: natural selection. |
The end of a pine tree branch bears the male cones that produce what?
Here are the choices:
A. the stigmas
B. oxygen
C. the ovaries
D. the pollen | John Haslam. The end of a pine tree branch bears the male cones that produce the pollen . CC BY 2.0. | D: the pollen. |
One seismogram indicates the distance to the what?
Here are the choices:
A. epicenter
B. researchers
C. the moon
D. houses | One seismogram indicates the distance to the epicenter. This is determined by the P-and S-wave arrival times. If a quake is near the seismograph, the S-waves arrive shortly after the P-waves. If a quake is far from the seismograph, the P-waves arrive long before the S-waves. The longer the time is between the P-and S-w... | A: epicenter. |
What is the process of creating complementary strands of mrna called?
Here are the choices:
A. differentiation
B. transcription
C. division
D. mutation | Overview of Transcription. Transcription uses the sequence of bases in a strand of DNA to make a complementary strand of mRNA. Triplets are groups of three successive nucleotide bases in DNA. Codons are complementary groups of bases in mRNA. Every triplet, or codon, encodes for a unique amino acid. | B: transcription. |
In ancient egypt gold mines were the property of what?
Here are the choices:
A. city
B. state
C. people
D. prospectors | But mining for gold is a slow, dirty, and dangerous process. Not everyone owns a gold mine – in both the ancient Egyptian society and during the Roman Empire, the gold mines were the property of the state, not an individual or group. So there were few ways for most people to legally get any gold for themselves. | B: state. |
The arid environment of a desert, for instance, can quickly deplete an animal of what?
Here are the choices:
A. water
B. air
C. strength
D. protein | A: water. | |
What type of chemistry is the study of chemicals containing carbon called?
Here are the choices:
A. bioanalytical chemistry
B. biochemistry
C. inorganic chemistry
D. organic chemistry | Organic chemistry is the study of chemicals containing carbon. Carbon is one of the most abundant elements on Earth and is capable of forming a tremendously vast number of chemicals (over twenty million so far). Most of the chemicals found in all living organisms are based on carbon. | D: organic chemistry. |
What is the muscular organ shaped like an upside-down pear that has a thick lining of tissues called the endometrium?
Here are the choices:
A. lungs
B. liver
C. uterus
D. kidney | The uterus is a muscular organ shaped like an upside-down pear. It has a thick lining of tissues called the endometrium . The lower, narrower end of the uterus is known as the cervix . The uterus is where a fetus grows and develops until birth. During pregnancy, the uterus can expand greatly to make room for the baby a... | C: uterus. |
What includes all the biotic and abiotic factors in an area and how they interact?
Here are the choices:
A. habitat
B. tundra
C. biome
D. ecosystem | An ecosystem is a unit of nature. It consists of all the biotic and abiotic factors in an area and all the ways in which they interact. | D: ecosystem. |
What is used for cooling detectors of infrared telescopes?
Here are the choices:
A. carbon dioxide
B. hand nitrogen
C. liquid nitrogen
D. material nitrogen | Detecting Electromagnetic Waves from Space A final note on star gazing. The entire electromagnetic spectrum is used by researchers for investigating stars, space, and time. As noted earlier, Penzias and Wilson detected microwaves to identify the background radiation originating from the Big Bang. Radio telescopes such ... | C: liquid nitrogen. |
What do we call something that pushes or pulls on an object?
Here are the choices:
A. annoyance
B. friction
C. reaction
D. force | 4.1 Development of Force Concept Dynamics is the study of the forces that cause objects and systems to move. To understand this, we need a working definition of force. Our intuitive definition of force—that is, a push or a pull—is a good place to start. We know that a push or pull has both magnitude and direction (ther... | D: force. |
Velocity is a vector that has both direction and what?
Here are the choices:
A. latitude
B. radiation
C. magnitude
D. variable | Because acceleration is velocity in m/s divided by time in s, the SI units for acceleration are m/s 2 , meters per second squared or meters per second per second, which literally means by how many meters per second the velocity changes every second. Recall that velocity is a vector—it has both magnitude and direction. ... | C: magnitude. |
What are the two classifications for organisms living in water?
Here are the choices:
A. arctan and nekton
B. scharwenka and plankton
C. nekton and plankton
D. arctan and plankton | Nekton are living things that swim through the water. They may live at any depth, in the photic or aphotic zone. Most nekton are fish, although some are mammals. Fish have fins and streamlined bodies to help them swim. Fish also have gills to take oxygen from the water. Figure below shows examples of nekton. | C: nekton and plankton. |
Where are hotspot volcanoes commonly found?
Here are the choices:
A. rivers
B. lakes
C. streams
D. the ocean | Hotspot volcanoes are better able to penetrate oceanic crust than continental crust. We see many more hotspot volcanoes in the oceans. | D: the ocean. |
The muscles of the anterior compartment of the lower leg are generally responsible for dorsiflexion, and the muscles of the posterior compartment of the lower leg are generally responsible for this?
Here are the choices:
A. walking flexion
B. plantar flexion
C. posterior flexion
D. ganglion flexion | Figure 11.32 Muscles of the Lower Leg The muscles of the anterior compartment of the lower leg are generally responsible for dorsiflexion, and the muscles of the posterior compartment of the lower leg are generally responsible for plantar flexion. The lateral and medial muscles in both compartments invert, evert, and r... | B: plantar flexion. |
The presence of what, which acts as a trigger, affects the rate of chemical reaction?
Here are the choices:
A. heat
B. friction
C. catalyst
D. light | rates The rates at which reactants are consumed and products are formed during chemical reactions vary greatly. We can identify five factors that affect the rates of chemical reactions: the chemical nature of the reacting substances, the state of subdivision (one large lump versus many small particles) of the reactants... | C: catalyst. |
What do you call the splitting of the nucleus of an atom into two smaller nuclei?
Here are the choices:
A. nuclear fusion
B. critical fission
C. cell division
D. nuclear fission | Nuclear fission is the splitting of the nucleus of an atom into two smaller nuclei. This type of reaction releases a great deal of energy from a very small amount of matter. For example, nuclear fission of a tiny pellet of uranium-235, like the one pictured in Figure below , can release as much energy as burning 1,000 ... | D: nuclear fission. |
What method is used to map the earth on flat paper?
Here are the choices:
A. forecasts
B. surveying
C. projections
D. calculations | Earth is a round, three-dimensional ball. In a small area, Earth looks flat, so it is not hard to make accurate maps of a small place. When mapmakers want to map the round Earth on flat paper, they use projections. What happens if you try to flatten out the skin of a peeled orange? Or if you try to gift wrap a soccer b... | C: projections. |
Water molds mostly live in water or moist?
Here are the choices:
A. soil
B. biomes
C. cells
D. plants | Define physical change, and give examples of physical change. | A: soil. |
What is the act of noting or detecting phenomenon through the senses
Here are the choices:
A. overstimulation
B. invention
C. an observation
D. sensory overload | Scientists first make observations that raise questions. An observation is the act of noting or detecting phenomenon through the senses. For example, noting that a room is dark is an observation made through sight. | C: an observation. |
What two measurements are multiplied to find the area of a rectangle?
Here are the choices:
A. length and depth
B. volume and mass
C. depth and width
D. length and width | Assume you are finding the area of a rectangle with a length of 6.8 m and a width of 6.9 m. When you multiply the length by the width on your calculator, the answer you get is 46.92 m 2 . Is this the correct answer? No; the correct answer is 46.9 m 2 . The correct answer must be rounded down so there is just one digit ... | D: length and width. |
What is the term for biologically meaningful dna sequences?
Here are the choices:
A. eggs
B. genes
C. babies
D. atoms | disease is sex-linked and effects mainly males (who are XY, compared to XX females).273 In the unaffected population, the FMR-1 gene contains between 6 to 50 copies of a CGG repeat. Individuals with between 6 to 50 repeats are phenotypically normal. Those with 50 to 200 repeats carry what is known as a pre-mutation; th... | B: genes. |
Which common type of diabetes is also known as noninsulin-dependent or adult-onset diabetes?
Here are the choices:
A. juvenile diabetes
B. type 2
C. type 1
D. gestational diabetes | inner aspect of the atlas, where it is held in place by a ligament. Rotation at this joint allows you to turn your head from side to side. A second pivot joint is found at the proximal radioulnar joint. Here, the head of the radius is largely encircled by a ligament that holds it in place as it articulates with the rad... | B: type 2. |
Recognition of pathogens is a function of what type of response?
Here are the choices:
A. inhalation
B. digestion
C. immune
D. hormones | Recognition of Pathogens Cells of the innate immune response, the phagocytic cells, and the cytotoxic NK cells recognize patterns of pathogenspecific molecules, such as bacterial cell wall components or bacterial flagellar proteins, using pattern recognition receptors. A pattern recognition receptor (PRR) is a membrane... | C: immune. |
Typically done to find food or mates, what do you call the regular movement of individuals or populations each year during certain seasons?
Here are the choices:
A. migration
B. industrialization
C. emmigration
D. erosion | Migration is another type of movement that changes population size. Migration is the regular movement of individuals or populations each year during certain seasons. The purpose of migration usually is to find food, mates, or other resources. For example, many northern hemisphere birds migrate thousands of miles south ... | A: migration. |
What is the vaccine to prevent infection of hpv?
Here are the choices:
A. HIV
B. gardasil
C. cervical
D. herpes | Infections with the human papillomavirus (HPV) are very common. HPV may cause genital warts , which are small, rough growths on the genitals. It may also cause cancer of the cervix in females. A simple test, called a Pap test , can detect cervical cancer . If the cancer is detected early, it usually can be cured with s... | B: gardasil. |
Mineral crystals that form when magma cools are usually _______ than crystals that form when lava cools.
Here are the choices:
A. denser
B. smaller
C. older
D. larger | Mineral crystals that form when magma cools are usually larger than crystals that form when lava cools. | D: larger. |
What element makes up the majority of coal?
Here are the choices:
A. iron
B. carbon
C. lead
D. silicon | Coal is a black or brownish-black rock that burns easily ( Figure below ). Most coal is sedimentary rock. The hardest type of coal, anthracite, is a metamorphic rock. That is because it is exposed to higher temperature and pressure as it forms. Coal is mostly carbon, but some other elements can be found in coal, includ... | B: carbon. |
What do you call a simple machine consisting of a sloping surface that connects lower and higher elevations?
Here are the choices:
A. wedge
B. inclined plane
C. lever
D. jack | An inclined plane is a simple machine consisting of a sloping surface that connects lower and higher elevations. The ideal mechanical advantage of an inclined plane is always greater than 1. | B: inclined plane. |
What can be combined with an amine to form an amide?
Here are the choices:
A. ketones
B. carboxylic acid
C. carbon dioxide
D. acetic acid | An amide can be formed by combining a carboxylic acid and an amine. Only primary and secondary amines can be used to form amides, since they have a hydrogen that can be replaced with the carbonyl carbon; tertiary amines will not form amides. The amide shown in the Figure above was formed from a carboxylic acid and a pr... | B: carboxylic acid. |
There are about 50,000 vertebrate species, and they are placed in how many different classes?
Here are the choices:
A. nine
B. ten
C. three
D. four | There are about 50,000 vertebrate species, and they are placed in nine different classes. Five of the classes are fish. The other classes are amphibians, reptiles, birds, and mammals. Table below lists some of the distinguishing traits of each class. | A: nine. |
In which kind of species do open circulatory systems serve additional functions?
Here are the choices:
A. some apes
B. some earthworms
C. some seedlings
D. some invertebrates | D: some invertebrates. | |
Boyle’s law applies to matter which is in what state?
Here are the choices:
A. gas
B. plasma
C. solids
D. liquids | A piston having a certain pressure and volume (left piston) will have half the volume when its pressure is twice as much (right piston). One can also plot P versus V for a given amount of gas at a certain temperature; such a plot will look like the graph on the right. Boyle’s law is an example of a second type of mathe... | A: gas. |
What do we call heated groundwater that erupts from the ground under pressure?
Here are the choices:
A. aquifers
B. spas
C. springs or geysers
D. volcanic eruptions | C: springs or geysers. | |
Sensory organs that respond to particular sensory stimuli contain cells called what?
Here are the choices:
A. stimulus receptor
B. artificial receptors
C. sensory receptors
D. whole receptors | Sensory organs such as the eyes contain cells called sensory receptors that respond to particular sensory stimuli. | C: sensory receptors. |
How can we reduce use of energy resources?
Here are the choices:
A. modification
B. conservation
C. liberation
D. restoration | We can reduce our use of energy resources and the pollution they cause by conserving energy. Conservation means saving resources by using them more efficiently or not using them at all. Figure below shows several ways that people can conserve energy in their daily lives. You can find more energy-saving tips at the URL ... | B: conservation. |
About 50% of all animal species died off between the mesozoic and which other era?
Here are the choices:
A. precambrian
B. jurassic
C. cenozoic
D. cretaceous | The most famous mass extinction was 65 million years ago. Between the Mesozoic Era and the Cenozoic Era, about 50% of all animal species died off. This mass extinction is when the dinosaurs became extinct. Most scientists think that the extinction was caused by a giant meteorite that struck Earth. The impact heated the... | C: cenozoic. |
Transforming from a caterpillar to a butterfly requires a lot of what?
Here are the choices:
A. Water
B. energy
C. fuel
D. food | This caterpillar is busily munching its way through leaf after leaf. In fact, caterpillars do little more than eat, day and night. Like all living things, they need food to provide their cells with energy. The caterpillar will soon go through an amazing transformation to become a beautiful butterfly. These changes requ... | B: energy. |
What two cycles make up the female reproductive cycle?
Here are the choices:
A. cervical and menstrual
B. ovarian and menstrual
C. digestive and menstrual
D. ovarian and cesarean | Female Hormones The control of reproduction in females is more complex. The female reproductive cycle is divided into the ovarian cycle and the menstrual cycle. The ovarian cycle governs the preparation of endocrine tissues and release of eggs, while the menstrual cycle governs the preparation and maintenance of the ut... | B: ovarian and menstrual. |
Uranium is an example of a non-renewable resource used to produce what type of power?
Here are the choices:
A. water
B. wind
C. electrical
D. nuclear | Some resources can’t be renewed. At least, they can’t be renewed fast enough to keep up with use. Fossil fuels are an example. It takes millions of years for them to form. We are using them up much more quickly. Elements that are used to produce nuclear power are also non-renewable resources. Uranium, for example, whic... | D: nuclear. |
One of the early signs of cell disease is this "leaking" of what into the body cells?
Here are the choices:
A. sodium ions
B. proteins
C. potassium ions
D. glucose | Potassium Concentration Glial cells, especially astrocytes, are responsible for maintaining the chemical environment of the CNS tissue. The concentrations of ions in the extracellular fluid are the basis for how the membrane potential is established and changes in electrochemical signaling. If the balance of ions is up... | A: sodium ions. |
What does the moving piston in an engine turn?
Here are the choices:
A. hammer
B. muffler
C. brake
D. crankshaft | D: crankshaft. | |
What type of chloride is a non-volatile material, but does not dissolve in water?
Here are the choices:
A. lead chloride
B. pink chloride
C. yellow chloride
D. silver chloride | Silver chloride is a non-volatile material, but does not dissolve in water. What effect will it have on the vapor pressure of water?. | D: silver chloride. |
In general, objects expand in all directions as temperature does what?
Here are the choices:
A. stays the same
B. increases
C. decreases
D. cycles | Figure 13.11 In general, objects expand in all directions as temperature increases. In these drawings, the original boundaries of the objects are shown with solid lines, and the expanded boundaries with dashed lines. (a) Area increases because both length and width increase. The area of a circular plug also increases. ... | B: increases. |
Paddles and hammers are examples of simple machines that increase the distance over which force is applied, while reducing what?
Here are the choices:
A. intensity
B. momentum
C. gravity
D. strength | Examples of machines that increase the distance over which force is applied are paddles and hammers. Figure below explains how these machines work. In each case, the machine increases the distance over which the force is applied, but it reduces the strength of the applied force. | D: strength. |
What two things collide to cause gas pressure?
Here are the choices:
A. light particles and an object
B. gas particles and a wave
C. gas particles and an object
D. gas particles and an electron | Gas pressure is the result of collisions between gas particles and an object. | C: gas particles and an object. |
Every human cell has the same what, and each cell has thousands of them?
Here are the choices:
A. ribosomes
B. chromosomes
C. DNA
D. genes | There are about 22,000 genes in every human cell. Does every human cell have the same genes? Yes. Does every human cell make the same proteins? No. In a multicellular organism, such as us, cells have specific functions because they have different proteins. They have different proteins because different genes are expres... | D: genes. |
What are a class of tetrapod vertebrates that produce amniotic eggs called?
Here are the choices:
A. insects
B. mammals
C. reptiles
D. amphibians | Reptiles are a class of tetrapod vertebrates that produce amniotic eggs. They include crocodiles, alligators, lizards, snakes, and turtles. The reptile class is one of the largest classes of vertebrates. It consists of all amniotes except birds and mammals. | C: reptiles. |
What characteristic of reptile eggs allows them to be laid on land instead of in water?
Here are the choices:
A. they trap gas
B. they are circular
C. they are amniotic
D. they are dry | Reptile eggs are amniotic, so they can be laid on land instead of in water. | C: they are amniotic. |
What part of the rainforest commonly has ferns and other ground plants?
Here are the choices:
A. understory
B. emergent layer
C. forest floor
D. canopy layer | Ferns are common in the understory of the tropical rainforest. | A: understory. |
The primary function of insulin is to facilitate the uptake of what into body cells?
Here are the choices:
A. sucralose
B. glucose
C. chloride
D. water | Insulin The primary function of insulin is to facilitate the uptake of glucose into body cells. Red blood cells, as well as cells of the brain, liver, kidneys, and the lining of the small intestine, do not have insulin receptors on their cell membranes and do not require insulin for glucose uptake. Although all other b... | B: glucose. |
Spindle fibers form between the centrioles during prophase i of what process?
Here are the choices:
A. photosynthesis
B. mitosis
C. meiosis
D. hydrolysis | Prophase I: Chromosomes form, and the nuclear membrane breaks down. Centrioles move to opposite poles of the cell. Spindle fibers form between the centrioles. Here’s what’s special about meiosis : Homologous chromosomes pair up! You can see this in Figure below . | C: meiosis. |
How many quarks are in each proton and neutron?
Here are the choices:
A. ten
B. five
C. four
D. three | Remember the quarks from the first page of this chapter? Quarks are even tinier particles of matter that make up protons and neutrons. There are three quarks in each proton and three quarks in each neutron. The charges of quarks are balanced exactly right to give a positive charge to a proton and a neutral charge to a ... | D: three. |
What is the year cycle that sunspots occur?
Here are the choices:
A. 15
B. 12
C. 22
D. 11 | The most noticeable magnetic activity of the Sun is the appearance of sunspots. Sunspots are cooler, darker areas on the Sun’s surface ( Figure below ). Sunspots occur in an 11-year cycle. The number of sunspots begins at a minimum. The number gradually increases to the maximum. Then the number returns to a minimum aga... | D: 11. |
When an unstable nucleus emits radiation and is transformed into the nucleus of other elements this is called?
Here are the choices:
A. naturally decay
B. explosive decay
C. fusion decay
D. radioactive decay | To balance a nuclear reaction. The two general kinds of nuclear reactions are nuclear decay reactions and nuclear transmutation reactions. In a nuclear decay reaction, also called radioactive decay, an unstable nucleus emits radiation and is transformed into the nucleus of one or more other elements. The resulting daug... | D: radioactive decay. |
What is manufactured and added to foods to preserve freshness?
Here are the choices:
A. trans fat
B. protein
C. vitamin c
D. carbohydrates | A type of lipid called trans fat is found in many processed foods. Trans fat is rare in nature but is manufactured and added to foods to preserve freshness. Eating foods that contain trans fat increases the risk of heart disease. Trans fat may be found in such foods as cookies, doughnuts, crackers, fried foods, ground ... | A: trans fat. |
Scientists think that stars and galaxies make up only a small part of the matter in the universe. what is the rest of the matter called?
Here are the choices:
A. dark matter
B. light matter
C. cold matter
D. typical matter | We see many objects out in space that emit light. This matter is contained in stars, and the stars are contained in galaxies. Scientists think that stars and galaxies make up only a small part of the matter in the universe. The rest of the matter is called dark matter . | A: dark matter. |
Why are noninfectious diseases not contagious?
Here are the choices:
A. they are contagious
B. they are inherited
C. they are viral
D. non-pathogen caused | Noninfectious diseases are not contagious because they are not caused by pathogens. Instead, they are caused by such factors as lifestyle choices, environmental toxins, or mutations. | D: non-pathogen caused. |
Organisms that "love" acids are known as what?
Here are the choices:
A. acidophiles
B. acidophobes
C. acid heads
D. acidic | Acidophiles are organisms that "love" acids. They live in very acidic environments, such as acid mine drainage. They are also found near vents of volcanoes. The most acidophilic archaeans can thrive at negative pH values. No other organisms can survive in such acidic conditions. | A: acidophiles. |
Which enzyme is used in step three of the polymerase chain reaction because of it's ability to withstand high temperatures?
Here are the choices:
A. taq polymerase
B. carbon polumerase
C. minocycline polymerase
D. backronym polymerase | When appropriate, a symbol may be written above or below the arrow to indicate some special circumstance. The symbol "Δ" is often used to indicate that the reaction is to be heated. | A: taq polymerase. |
What do scientists use to study the deep without going to the seafloor?
Here are the choices:
A. remotely operated vehicles
B. telescopes
C. ultrasound machines
D. drill rigs | Sending humans to the seafloor is expensive and dangerous. Having to return humans safely to the surface limits what a mission can do. Remotely operated vehicles , or ROVs, allow scientists to study the deep without going to the seafloor. These small vehicles carry cameras and scientific instruments. ROVs were used to ... | A: remotely operated vehicles. |
The hemisphere that is tilted away from the sun is cooler because it receives less what?
Here are the choices:
A. direct rays
B. x-rays
C. direct electrons
D. pollution | The hemisphere that is tilted away from the Sun is cooler because it receives less direct rays. As Earth orbits the Sun, the Northern Hemisphere goes from winter to spring, then summer and fall. The Southern Hemisphere does the opposite from summer to fall to winter to spring. When it is winter in the Northern hemisphe... | A: direct rays. |
Like the strings of cello, anything that vibrates produces waves of what?
Here are the choices:
A. energy
B. light
C. heating
D. sound | A: Like the strings of cello, anything that vibrates produces waves of energy that travel through matter. For example, when you throw a pebble into a pond, waves of energy travel from the pebble through the water in all directions. Like an incandescent light bulb, anything that glows consists of matter that produces li... | A: energy. |
The point in the titration at which an indicator changes color is called what?
Here are the choices:
A. chromatic point
B. zeta point
C. end point
D. tipping point | Acid–Base Titrations Because most common acids and bases are not intensely colored, a small amount of an acid– base indicator is usually added to detect the equivalence point in an acid–base titration. The point in the titration at which an indicator changes color is called theendpoint. The procedure is illustrated in ... | C: end point. |
On a hot, dry day, plants close their stomata to conserve what?
Here are the choices:
A. water
B. cold
C. sunlight
D. air | ART CONNECTION QUESTIONS 1. Figure 5.7 On a hot, dry day, plants close their stomata to conserve water. What impact will this have on photosynthesis?. | A: water. |
What do you call the system of glands that release chemical messenger molecules into the bloodstream?
Here are the choices:
A. limbic system
B. endocrine system
C. homeostasis system
D. nervous system | The nervous system isn’t the only message-relaying system of the human body. The endocrine system also carries messages. The endocrine system is a system of glands that release chemical messenger molecules into the bloodstream. The messenger molecules are hormones. Hormones act slowly compared with the rapid transmissi... | B: endocrine system. |
Reactant concentrations are highest at which part of a reaction?
Here are the choices:
A. concurrent
B. middle
C. ending
D. beginning | Reactant concentrations are highest at the beginning of a reaction. The plot of [C] versus tis a curve with a slope that becomes steadily less positive. | D: beginning. |
What happens to the temperature of a system during phase change?
Here are the choices:
A. increases
B. remains constant
C. decreases
D. fluctuates rapidly | This plot of temperature shows what happens to a 75 g sample of ice initially at 1 atm and −23°C as heat is added at a constant rate: A–B: heating solid ice; B–C: melting ice; C–D: heating liquid water; D– E: vaporizing water; E–F: heating steam. Thus the temperature of a system does not change during a phase change. I... | B: remains constant. |
What is the major cause of outdoor air pollution?
Here are the choices:
A. electric lines
B. manufacturing industry
C. agricultural equipment
D. burning fossil fuels | The major cause of outdoor air pollution is the burning of fossil fuels. Fossil fuels are burned in power plants, factories, motor vehicles, and home heating systems. Ranching and using chemicals such as fertilizers also cause outdoor air pollution. Erosion of soil in farm fields, mining activities, and construction si... | D: burning fossil fuels. |
Why does a metal spoon heat up quickly when placed in a hot drink?
Here are the choices:
A. low specific heat
B. insulation
C. convection
D. high specific heat | The Table below compares the specific heat of four different substances. Metals such as iron have low specific heat. It doesn’t take much energy to raise their temperature. That’s why a metal spoon heats up quickly when placed in a cup of hot coffee. Sand also has a relatively low specific heat. Water, on the other han... | A: low specific heat. |
What does the megaspore mother cell produce after meiosis division?
Here are the choices:
A. two haploid megaspores
B. two diploid megapores
C. four diploid megaspores
D. four haploid megaspores | Watch this video (http://openstaxcollege. org/l/pollen_release) to see a cedar releasing its pollen in the wind. Female Gametophyte The female cone also has a central axis on which bracts known as megasporophylls (Figure 32.10) are present. In the female cone, megaspore mother cells are present in the megasporangium. T... | D: four haploid megaspores. |
Synaptic connections can change over time depending on what?
Here are the choices:
A. activity level
B. age
C. weight
D. diet | A: activity level. | |
What is the body of a roundworm covered with?
Here are the choices:
A. thin epidermis
B. slime
C. thick scales
D. tough cuticle | Roundworms have a pseudocoelom and hydrostatic skeleton. Their body is covered with tough cuticle. | D: tough cuticle. |
The end of the phospholipid molecule that is polar and attracts water is called what?
Here are the choices:
A. hydrophobic
B. hydrophilic
C. magnetic
D. cytosolic | Figure below shows how phospholipid molecules are arranged in a cell membrane. One end (the head) of each phospholipid molecule is polar and attracts water. This end is called hydrophilic ("water loving"). The other end (the tail) is nonpolar and repels water. This end is called hydrophobic ("water hating"). The nonpol... | B: hydrophilic. |
What is known as the universal solvent?
Here are the choices:
A. water
B. air
C. oil
D. vinegar | The ability of a solute to dissolve in a particular solvent is called solubility . Many chemical substances are soluble in water. In fact, so many substances are soluble in water that water is called the universal solvent. Water is a strongly polar solvent, and polar solvents are better at dissolving polar solutes. Man... | A: water. |
Any organism that causes disease is called what?
Here are the choices:
A. a parasite
B. a pathogen
C. a microbe
D. a virus | You have ten times as many bacterial cells as human cells in your body. Luckily for you, most of these bacteria are harmless. However, some of them can cause disease. Any organism that causes disease is called a pathogen . Diseases caused by bacterial pathogens include food poisoning, strep throat, and Lyme disease. | B: a pathogen. |
Electric generators change kinetic energy to what type of energy?
Here are the choices:
A. electrical
B. light
C. intrinsic
D. thermal | Sources of voltage include electric generators and cells. Electric generators change kinetic energy to electrical energy. Chemical cells change chemical energy to electrical energy, and solar cells change solar energy to electrical energy. | A: electrical. |
Brown algae are important commodities for what?
Here are the choices:
A. fish
B. parasites
C. reptiles
D. humans | D: humans. | |
What does the large central vacuole do?
Here are the choices:
A. use water
B. heat water
C. store water
D. create glucose | First, plant cells have a large central vacuole that holds a mixture of water, nutrients, and wastes. A plant cell's vacuole can make up 90% of the cell’s volume. The large central vacuole essentially stores water. In animal cells, vacuoles are much smaller. | C: store water. |
What is the ratio of solutes in a solution to a volume of solvent in a solution known as?
Here are the choices:
A. osmolality
B. molarity
C. equilibrium
D. molality | Regulation of Water Intake Osmolality is the ratio of solutes in a solution to a volume of solvent in a solution. Plasma osmolality is thus the ratio of solutes to water in blood plasma. A person’s plasma osmolality value reflects his or her state of hydration. A healthy body maintains plasma osmolality within a narrow... | A: osmolality. |
What type of rock contains concentrations of valuable minerals?
Here are the choices:
A. metamorphic
B. ores
C. igneous
D. sedimentary | A mineral deposit that contains enough minerals to be mined for profit is called an ore . Ores are rocks that contain concentrations of valuable minerals. The bauxite shown in the Figure below is a rock that contains minerals that are used to make aluminum. | B: ores. |
How many digits do primates have on each extremity?
Here are the choices:
A. ten
B. four
C. five
D. three | Primates have five digits (fingers or toes) on each extremity. Unlike the hooves of horses or the paddles of whales, the digits of primates are relatively unspecialized. Therefore, they can be used to do a variety of tasks, including grasping branches and holding tools. | C: five. |
Dna is normally found within what region of a cell?
Here are the choices:
A. Golgi apparatus
B. genome sequence
C. mitochondria
D. nucleus | the nucleus. The nucleus contains one or more nucleoli, which serve as sites for ribosome synthesis. The nucleus houses the genetic material of the cell: DNA. DNA is normally found as a loosely contained structure called chromatin within the nucleus, where it is wound up and associated with a variety of histone protein... | D: nucleus. |
Water and carbon dioxide molecules are reactants in what plant process?
Here are the choices:
A. digestion
B. breathing
C. photosynthesis
D. glycolysis | Water and carbon dioxide molecules are reactants in the process of photosynthesis. Does this mean they are “food” for plants, algae, and blue-green bacteria? Use the definition of “food” to answer this question. | C: photosynthesis. |
Gene therapy is a type of what kind of engineering?
Here are the choices:
A. genetic engineering
B. mechanical engineering
C. chemical engineering
D. electrical engineering | Biotechnology in Medicine and Agriculture It is easy to see how biotechnology can be used for medicinal purposes. Knowledge of the genetic makeup of our species, the genetic basis of heritable diseases, and the invention of technology to manipulate and fix mutant genes provides methods to treat the disease. Biotechnolo... | A: genetic engineering. |
What is mass number?
Here are the choices:
A. to total number of protons and electrons in a nucleus
B. the total number of protons and chondrichthyes in a nucleus
C. the total number of protons and neutrons in a nucleus
D. to total number of electrons and neutrons in a nucleus | All oxygen atoms have eight protons, and most have eight neutrons as well. What is the mass number of an oxygen isotope that has nine neutrons? What is the name of this isotope?. | C: the total number of protons and neutrons in a nucleus. |
What rises through solid rocks where conditions are right?
Here are the choices:
A. magma
B. nitrogen
C. water
D. crystals | Lithospheric plates do a lot of moving on Earth's surface. Slabs of lithosphere smash into each other. They move sideways past each other along faults. Where conditions are right, magma rises through solid rock. It's no wonder that rocks experience stress! Rocks respond differently to different types of stress and unde... | A: magma. |
What is the connecting piece of a sperm packed with?
Here are the choices:
A. Gelatin
B. mitochondria
C. glucose
D. protein | The connecting piece of the sperm is packed with mitochondria. Mitochondria are organelles in cells that produce energy. Sperm use the energy to move. | B: mitochondria. |
What is a diagram that shows a single way that energy flows throughout an ecosystem?
Here are the choices:
A. food chain
B. dependent chain
C. water cycle
D. fuel chain | A food chain is a simple diagram that shows one way energy flows through an ecosystem. Pictured below is an example of a food chain ( Figure below ). Producers form the base of all food chains. The consumers that eat producers are called primary consumers. The consumers that eat primary consumers are secondary consumer... | A: food chain. |
Different colors of light differ in terms of which important attribute?
Here are the choices:
A. prisms
B. frequencies
C. lenses
D. wavelengths | Nobody really has such colorful eyes! The colors were added digitally after the photo was taken. They represent all the different colors of light. Light is a form of energy that travels in waves. Light of different colors has different wavelengths. | D: wavelengths. |
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