questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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What determines velocity?
Here are the choices:
A. distance over time in a given direction
B. mass per unit
C. direction
D. change in direction | Figure 28.14 Classically, velocities add like ordinary numbers in one-dimensional motion. Here the girl throws a snowball forward and then backward from a sled. The velocity of the sled relative to the Earth is relative to the Earth is. | A: distance over time in a given direction. |
What term is used to describe a simple diagram that shows one way energy flows through an ecosystem?
Here are the choices:
A. fuel chain
B. water cycle
C. food chain
D. food pyramid | A food chain is a simple diagram that shows one way energy flows through an ecosystem. You can see an example of a food chain in 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 consumers. This chain can continue to multiple levels. | C: food chain. |
How can nuclear fusion in stars be simulated?
Here are the choices:
A. plutonium accelerators
B. nuclear reactors
C. nitrogen accelerators
D. particle accelerators | Particle accelerators simulate nuclear fusion in stars. | D: particle accelerators. |
What type of tissue transmits nerve impulses throughout the body?
Here are the choices:
A. fibrous
B. nervous
C. epithelial
D. connective | B: nervous. | |
Animals produce most of what chemicals, which are needed to synthesize the fatty acids they need?
Here are the choices:
A. solvents
B. carbohydrates
C. hormones
D. enzymes | D: enzymes. | |
How do parathyroid hormones react as a body ages?
Here are the choices:
A. decrease with age
B. increase with age
C. use with age
D. help with age | Low levels of estrogens and progesterone are also associated with some disease states, such as osteoporosis, atherosclerosis, and hyperlipidemia, or abnormal blood lipid levels. Testosterone levels also decline with age, a condition called andropause (or viropause); however, this decline is much less dramatic than the decline of estrogens in women, and much more gradual, rarely affecting sperm production until very old age. Although this means that males maintain their ability to father children for decades longer than females, the quantity, quality, and motility of their sperm is often reduced. As the body ages, the thyroid gland produces less of the thyroid hormones, causing a gradual decrease in the basal metabolic rate. The lower metabolic rate reduces the production of body heat and increases levels of body fat. Parathyroid hormones, on the other hand, increase with age. This may be because of reduced dietary calcium levels, causing a compensatory increase in parathyroid hormone. However, increased parathyroid hormone levels combined with decreased levels of calcitonin (and estrogens in women) can lead to osteoporosis as PTH stimulates demineralization of bones to increase blood calcium levels. Notice that osteoporosis is common in both elderly males and females. Increasing age also affects glucose metabolism, as blood glucose levels spike more rapidly and take longer to return to normal in the elderly. In addition, increasing glucose intolerance may occur because of a gradual decline in cellular insulin sensitivity. Almost 27 percent of Americans aged 65 and older have diabetes. | B: increase with age. |
What describe the fraction or percentage of a mixture that is made up of a particular substance.
Here are the choices:
A. atomic weight
B. molecular scale
C. mole fractions
D. solute level | Mole fractions describe the fraction or percentage of a mixture that is made up of a particular substance. | C: mole fractions. |
What are the most numerous organisms in the world?
Here are the choices:
A. jellyfish
B. insects
C. primates
D. reptiles | Insects are arthropods in the class Hexapoda. They are the most numerous organisms in the world. | B: insects. |
What helps push the fetus from the uterus during birth?
Here are the choices:
A. tremors
B. contractions
C. glands
D. Shaking | Near the time of birth, the amniotic sac breaks in a gush of liquid. Labor usually begins within a day of this event. Labor involves contractions of the muscular walls of the uterus. With the mother’s help, the contractions eventually push the fetus out of the uterus and through the vagina. | B: contractions. |
Telescopes use which kind of lenses to enlarge images?
Here are the choices:
A. convex
B. concave
C. crystalline
D. spherical | Like microscopes, telescopes use convex lenses to make enlarged images. However, telescopes make enlarged images of objects—such as distant stars—that only appear tiny because they are very far away. There are two basic types of telescopes: reflecting telescopes and refracting telescopes. The two types are compared in the Figure below . They differ in how they collect light, but both use convex lenses to form enlarged images. You can learn more about telescopes and how they evolved in the video at this URL:. | A: convex. |
How does uric acid react to water?
Here are the choices:
A. explodes
B. mixes
C. does not dissolve
D. does not form | C: does not dissolve. | |
Which kingdom are mosses and trees included in?
Here are the choices:
A. plant
B. gymnosperm
C. protista
D. fungus | Mateusz Kulawik. Mosses and trees are all part of the plant kingdom . CC BY 2.0. | A: plant. |
What is the developing human organism referred to as from the end of the eighth week until birth?
Here are the choices:
A. fetus
B. egg
C. nucleus
D. babies | From the end of the eighth week until birth, the developing human organism is referred to as a fetus . Birth typically occurs at about 38 weeks after fertilization, so the fetal period generally lasts about 30 weeks. During this time, as outlined in Figure below , the organs complete their development. The fetus also grows rapidly in length and weight. | A: fetus. |
In an acidic medium, add which ions to balance?
Here are the choices:
A. hydrogen
B. helium
C. magnesium
D. calcium | Now the hydrogen atoms need to be balanced. In an acidic medium, add hydrogen ions to balance . In this example, fourteen H + ions will be added to the reactant side. | A: hydrogen. |
Which type of plankton make food via photosynthesis?
Here are the choices:
A. common plankton
B. phytoplankton
C. dinoflagellates
D. zooplankton | Phytoplankton are “plant-like” plankton. Since they make food by photosynthesis, they live in the photic zone. Most are algae. | B: phytoplankton. |
What is capable of altering the rate of time passing?
Here are the choices:
A. weak gravitational fields
B. strong gravitational fields
C. strong planetary fields
D. strong magnetic fields | Strong gravitational fields can alter the rate of time passing. True. | B: strong gravitational fields. |
Damages and deaths are directly affected by what in an earthquake?
Here are the choices:
A. shaking
B. natural
C. structures
D. construction | The type of construction has a tremendous effect on what happens during an earthquake. Damage and deaths are directly affected by the construction in an earthquake. For example, enormous damage was done in the 2011 Christchurch, New Zealand earthquake. However, far less was damaged in an earthquake of the same magnitude near the area in Iceland seen above. | D: construction. |
What is the the basic si unit for mass?
Here are the choices:
A. density
B. kilogram (kg)
C. volume
D. pound | Mass measures the amount of matter in a substance or an object. The basic SI unit for mass is the kilogram (kg). | B: kilogram (kg). |
What are objects that are launched into the air called?
Here are the choices:
A. booms
B. stones
C. projectiles
D. shoots | Objects that are launched into the air are called projectiles . The path followed by a projectile in motion is called a trajectory . The image of the snowboarder in the chapter introduction showed his trajectory; every object has a trajectory even when we cannot see it. Projectile motion , or the object's trajectory, is described in terms of position, velocity, and acceleration. Even with only an object's current location, velocity, and acceleration, we can calculate when and where the object will land. Our knowledge that perpendicular components of vectors do not affect each other allow us to easily analyze the motion of projectiles. | C: projectiles. |
What are hydrocarbons with double bonds called?
Here are the choices:
A. amines
B. alkenes
C. alcohols
D. aldehydes | Unsaturated hydrocarbons contain at least one double or triple bond between carbon atoms. Hydrocarbons with double bonds are called alkenes. Those with triple bonds are called alkynes. Aromatic hydrocarbons consist of six carbon atoms in a ring shape, connected by alternating single and double bonds. | B: alkenes. |
What is the liquid component in blood?
Here are the choices:
A. hemoglobin
B. aqueous humor
C. respiration
D. plasma | Blood is a fluid connective tissue that contains a liquid component called plasma. | D: plasma. |
Functional groups are groups of atoms that occur within molecules and confer specific chemical properties to those molecules. they are found along the “carbon backbone” of what?
Here are the choices:
A. inorganic molecules
B. functional molecules
C. micromolecules
D. macromolecules | Functional Groups Functional groups are groups of atoms that occur within molecules and confer specific chemical properties to those molecules. They are found along the “carbon backbone” of macromolecules. This carbon backbone is formed by chains and/or rings of carbon atoms with the occasional substitution of an element such as nitrogen or oxygen. Molecules with other elements in their carbon backbone are substituted hydrocarbons. The functional groups in a macromolecule are usually attached to the carbon backbone at one or several different places along its chain and/or ring structure. Each of the four types of macromolecules—proteins, lipids, carbohydrates, and nucleic acids—has its own characteristic set of functional groups that contributes greatly to its differing chemical properties and its function in living organisms. | D: macromolecules. |
Predators can replace what tool in agriculture.
Here are the choices:
A. pesticides
B. irrigators
C. fertilizer
D. harvesters | Predator species such as birds and spiders control insect pests. They reduce the need for chemical pesticides, which are expensive and may be harmful to human beings and other organisms. | A: pesticides. |
What is a mixture of eroded rock, minerals, partly decomposed organic matter, and other materials called?
Here are the choices:
A. sediment
B. loam
C. soil
D. sand | Soil is a mixture of eroded rock, minerals, partly decomposed organic matter, and other materials. It is essential for plant growth, so it is the foundation of terrestrial ecosystems. Soil is important for other reasons as well. For example, it removes toxins from water and breaks down wastes. | C: soil. |
All cells need what for energy?
Here are the choices:
A. oxygen
B. insulin
C. light
D. glucose | Glucose is a substance that passes across cell membranes by facilitated diffusion. All cells need glucose for energy. | D: glucose. |
In an experiment, what is the affected variable called?
Here are the choices:
A. control variable
B. independent variable
C. form variable
D. dependent variable | An experiment generally tests how one variable is affected by another. The affected variable is called the dependent variable . In the plant experiment shown above, the dependent variable is plant growth. The variable that affects the dependent variable is called the independent variable . In the plant experiment, the independent variable could be fertilizer—some plants will get fertilizer, others will not. The scientists change the amount of the independent variable (the fertilizer) to observe the effects on the dependent variable (plant growth). An experiment needs to be run simultaneously in which no fertilizer is given to the plant. This would be known as a control experiment. In any experiment, other factors that might affect the dependent variable must be controlled. In the plant experiment, what factors do you think should be controlled? ( Hint: What other factors might affect plant growth?). | D: dependent variable. |
Does the stream-lined body featured on most fish increase or decrease water resistance?
Here are the choices:
A. quickens
B. increases
C. decrease
D. precipitates | Fish typically have a stream-lined body. This reduces water resistance. | C: decrease. |
What is the role of the sodium ion in the neutralization reaction of sodium flouride?
Here are the choices:
A. reflection ion
B. spectator ion
C. circuit ion
D. team ion | Since sodium fluoride is soluble, the sodium ion is a spectator ion in the neutralization reaction. The fluoride ion is capable of reacting, to a small extent, with water, accepting a proton. | B: spectator ion. |
What is the name of the line used in topographic maps that shows different elevations?
Here are the choices:
A. a patch line
B. a curve line
C. a contour line
D. a crater line | Mapping is an important part of Earth Science. Topographic maps use a line, called a contour line, to show different elevations on a map. Contour lines show the location of hills, mountains and valleys. A regular road map shows where a road goes. But a road map doesn’t show if the road goes over a mountain pass or through a valley. A topographic map shows you the features the road is going through or past. Let’s look at topographic maps. | C: a contour line. |
Sporangia produce spores that develop into tiny, heart-shaped what?
Here are the choices:
A. gametophytes
B. tubules
C. filaments
D. cells | A mature sporophyte fern has the familiar leafy fronds. The undersides of the leaves are dotted with clusters of sporangia. Sporangia produce spores that develop into tiny, heart-shaped gametophytes. Gametophytes have antheridia and archegonia. Antheridia produce sperm with many cilia; archegonia produce eggs. Fertilization occurs when sperm swim to an egg inside an archegonium. The resulting zygote develops into an embryo that becomes a new sporophyte plant. Then the cycle repeats. | A: gametophytes. |
A long chain of mountains that rises up high above the deep seafloor is called?
Here are the choices:
A. mid-ocean ridges
B. blue ridge mountains
C. oceanic alps
D. sea mounds | mid-ocean ridges : A long chain of mountains that rises up high above the deep seafloor. An example is the light blue gash in middle of Atlantic Ocean. Light blue is higher elevation than dark blue. | A: mid-ocean ridges. |
When bacteria are destroyed by leukocytes, what are released into the blood?
Here are the choices:
A. proteins
B. pyrogens
C. sporozoans
D. carcinogens | When bacteria are destroyed by leukocytes, pyrogens are released into the blood. Pyrogens reset the body’s thermostat to a higher temperature, resulting in fever. How might pyrogens cause the body temperature to rise?. | B: pyrogens. |
Hierarchical classification can reflect the branching patterns of phylogenetic?
Here are the choices:
A. trees
B. animals
C. fruits
D. birds | A: trees. | |
Unstable isotopes give off particles and energy as what?
Here are the choices:
A. radiation
B. radioactivity
C. electricity
D. ultraviolet light | B: radioactivity. | |
What structure is an organelle that contains enzymes that break down and digest unneeded cellular components?
Here are the choices:
A. lysosome
B. centrosome
C. peroxisome
D. tissue | Lysosomes Some of the protein products packaged by the Golgi include digestive enzymes that are meant to remain inside the cell for use in breaking down certain materials. The enzyme-containing vesicles released by the Golgi may form new lysosomes, or fuse with existing, lysosomes. A lysosome is an organelle that contains enzymes that break down and digest unneeded cellular components, such as a damaged organelle. (A lysosome is similar to a wrecking crew that takes down old and unsound buildings in a neighborhood. ) Autophagy (“self-eating”) is the process of a cell digesting its own structures. Lysosomes are also important for breaking down foreign material. For example, when certain immune defense cells (white blood cells) phagocytize bacteria, the bacterial cell is transported into a lysosome and digested by the enzymes inside. As one might imagine, such phagocytic defense cells contain large numbers of lysosomes. Under certain circumstances, lysosomes perform a more grand and dire function. In the case of damaged or unhealthy cells, lysosomes can be triggered to open up and release their digestive enzymes into the cytoplasm of the cell, killing the cell. This “self-destruct” mechanism is called autolysis, and makes the process of cell death controlled (a mechanism called “apoptosis”). | A: lysosome. |
What is the unit used to measure voltage?
Here are the choices:
A. volts
B. ampere
C. ohm
D. watt | Electric current occurs whenever there is a difference in electric potential energy, or voltage. Voltage is measured in volts (V). | A: volts. |
What type of gases are used for balloons, light bulbs and lighted signs?
Here are the choices:
A. helium
B. heavy
C. ignoble
D. noble | Noble gases are used for balloons, light bulbs, and lighted signs. | D: noble. |
Some living things on the ocean floor are sources of what human necessity?
Here are the choices:
A. hormones
B. steroids
C. pesticides
D. medicines | The ocean floor is home to many species of living things. Some from shallow water are used by people for food. Clams and some fish are among the many foods we get from the ocean floor. Some living things on the ocean floor are sources of human medicines. For example, certain bacteria on the ocean floor produce chemicals that fight cancer. | D: medicines. |
Many protists form what kind of beneficial association with other species?
Here are the choices:
A. Opportunistic
B. evolved
C. symbiotic
D. Facultative | C: symbiotic. | |
When two of these meet, the result is often a storm?
Here are the choices:
A. air masses
B. electromagnetic waves
C. tectonic plates
D. air pockets | In displacement versus time graphs, the slope of the line is the velocity of the object. In this case of a velocity versus time graph, the slope of the line is the acceleration. If you take any segment of this line and determine the to ratio, you will get 6.0 m/s 2 which we know to be the constant acceleration of this object. | A: air masses. |
What causes food to move through the esophagus?
Here are the choices:
A. proteolysis
B. peristalsis
C. photosynthesis
D. apoptosis | The esophagus is a narrow tube that carries food from the throat to the stomach. Food moves through the esophagus because of peristalsis. At the lower end of the esophagus, a circular muscle controls the opening to the stomach. The muscle relaxes to let food pass into the stomach. Then the muscle contracts again to prevent food from passing back into the esophagus. | B: peristalsis. |
What do we call the solid form of hydrocarbons?
Here are the choices:
A. methane
B. shale
C. coal
D. bauxite | Fossil fuels are compounds of carbon and hydrogen, called hydrocarbons . Hydrocarbons can be solid, liquid, or gas. The solid form is coal. The liquid form is petroleum, or crude oil. The gaseous form is natural gas. | C: coal. |
What is needed to create muscles, regulate chemical reactions, and transport oxygen?
Here are the choices:
A. enzymes
B. cytoplasm
C. proteins
D. lipids | Your body needs proteins to create muscles, regulate chemical reactions, transport oxygen, and perform other important tasks in your body. But how are these proteins built? They are made up of units called amino acids. Just like there are only a few types of blocks in a set, there are a limited number of amino acids. But there are many different ways in which they can be combined. | C: proteins. |
What does the vertebral column , or backbone, protect?
Here are the choices:
A. spinal cord
B. neurons
C. disks
D. axons | The primary feature shared by all vertebrates is the vertebral column , or backbone. The vertebral column protects the spinal cord. | A: spinal cord. |
X rays and what other type of electromagnetic wave has the shortest wavelengths and the highest frequencies?
Here are the choices:
A. plasma rays
B. X-rays
C. ultraviolet rays
D. gamma rays | On the far right are X rays and gamma rays. The have the shortest wavelengths and highest frequencies of all electromagnetic waves. They also have the greatest amount of energy. | D: gamma rays. |
The anterior pituitary produces seven different what, each with a special function?
Here are the choices:
A. proteins
B. neurotransmitters
C. enzymes
D. hormones | Anterior Pituitary The anterior pituitary gland, or adenohypophysis, is surrounded by a capillary network that extends from the hypothalamus, down along the infundibulum, and to the anterior pituitary. This capillary network is a part of the hypophyseal portal system that carries substances from the hypothalamus to the anterior pituitary and hormones from the anterior pituitary into the circulatory system. A portal system carries blood from one capillary network to another; therefore, the hypophyseal portal system allows hormones produced by the hypothalamus to be carried directly to the anterior pituitary without first entering the circulatory system. The anterior pituitary produces seven hormones: growth hormone (GH), prolactin (PRL), thyroid-stimulating hormone (TSH), melanin-stimulating hormone (MSH), adrenocorticotropic hormone (ACTH), follicle-stimulating hormone (FSH), and luteinizing hormone (LH). Anterior pituitary hormones are sometimes referred to as tropic hormones, because they. | D: hormones. |
What is the term for the measure of the average kinetic energy of the particles in matter?
Here are the choices:
A. voltage
B. precipitation
C. friction
D. temperature | Temperature is a measure of the average kinetic energy of the particles in matter. | D: temperature. |
Pepsin and trypsin are examples of enzymes involved in what bodily process?
Here are the choices:
A. perspiration
B. regeneration
C. filtration
D. digestion | Various conditions affect enzyme function. Pepsin and trypsin are two digestive enzymes that work in contrasting environments. | D: digestion. |
What is the only metalloid in group 13?
Here are the choices:
A. boron
B. alluminum
C. phosphorus
D. gallium | Group 13 is called the boron group, and boron is the only metalloid in this group. The other group 13 elements are metals. | A: boron. |
How is a mammal developed if not inside of a placenta or a pouch?
Here are the choices:
A. spawning or budding
B. mitosis
C. hatched from eggs
D. cloning | This is a mammal. But it is unlike placental or marsupial mammals. If a mammal does not develop within a placenta or a pouch, what type of development is left? Eggs!. | C: hatched from eggs. |
Slime molds have several morphological similarities to fungi, including spore-generation, that are thought to be the result of convergent what?
Here are the choices:
A. evolution
B. generation
C. emergence
D. phenomenon | Slime Molds A subset of the amoebozoans, the slime molds, has several morphological similarities to fungi that are thought to be the result of convergent evolution. For instance, during times of stress, some slime molds develop into spore-generating fruiting bodies, much like fungi. The slime molds are categorized on the basis of their life cycles into plasmodial or cellular types. Plasmodial slime molds are composed of large, multinucleate cells and move along surfaces like an amorphous blob of slime during their feeding stage (Figure 23.27). Food particles are lifted and engulfed into the slime mold as it glides along. Upon maturation, the plasmodium takes on a net-like appearance with the ability to form fruiting bodies, or sporangia, during times of stress. Haploid spores are produced by meiosis within the sporangia, and spores can be disseminated through the air or water to potentially land in more favorable environments. If this occurs, the spores germinate to form ameboid or flagellate haploid cells that can combine with each other and produce a diploid zygotic slime mold to complete the life cycle. | A: evolution. |
What do willow trees produce to kill bacteria?
Here are the choices:
A. chlorophyll
B. salicylic acid
C. cytoplasmic acid
D. enzymes | Plants don’t have immune systems, but they do respond to disease. Typically, their first line of defense is the death of cells surrounding infected tissue. This prevents the infection from spreading. Many plants also produce hormones and toxins to fight pathogens. For example, willow trees produce salicylic acid to kill bacteria. The same compound is used in many acne products for the same reason. Exciting new research suggests that plants may even produce chemicals that warn other plants of threats to their health, allowing the plants to prepare for their own defense. As these and other responses show, plants may be rooted in place, but they are far from helpless. | B: salicylic acid. |
The ph scale is a scale used to express the concentration of hydrogen ions in solution. a neutral solution, neither acidic nor basic, has a ph of what?
Here are the choices:
A. 8
B. 0
C. 7
D. 6 | dissociated ions. It is a dynamic equilibrium because acid and base molecules are constantly dissociating into ions and reassociating into neutral molecules. The pH scale is a scale used to express the concentration of hydrogen ions in solution. A neutral solution, neither acidic nor basic, has a pH of 7. Acidic solutions have a pH lower than 7, while basic solutions have a pH higher than 7. Buffers are solutions that resist dramatic changes in pH when an acid or a base is added to them. They contain a weak acid and a salt of that weak acid, or a weak base and a salt of that weak base. When a buffer is present, any strong acid reacts with the anion of the salt, forming a weak acid and minimizing the presence of hydrogen ions in solution. Any strong base reacts with the weak acid, minimizing the amount of additional hydroxide ions in solution. However, buffers only have limited capacity; there is a limit to the amount of strong acid or strong base any given amount of buffer will react with. | C: 7. |
What is the term for something left behind by once-living organisms?
Here are the choices:
A. waste matter
B. deposits
C. decay
D. fossils | Most sedimentary rocks form from sediments. Sediments are small pieces of other rocks, like pebbles, sand, silt, and clay. Sedimentary rocks may include fossils. Fossils are materials left behind by once-living organisms. Fossils can be pieces of the organism, like bones. They can also be traces of the organism, like footprints. | D: fossils. |
What connects the peripheral nervous system to the central nervous system?
Here are the choices:
A. veins
B. wires
C. nerves
D. fibers | The peripheral nervous system consists of all the nervous tissue that lies outside the central nervous system. It is connected to the central nervous system by nerves. | C: nerves. |
In which supergroup are red algae and green algae included?
Here are the choices:
A. archaeplastida
B. xerophyte
C. spirogyra
D. troglodyte | Archaeplastida Red algae and green algae are included in the supergroup Archaeplastida. It was from a common ancestor of these protists that the land plants evolved, since their closest relatives are found in this group. Molecular evidence supports that all Archaeplastida are descendents of an endosymbiotic relationship between a heterotrophic protist and a cyanobacterium. The red and green algae include unicellular, multicellular, and colonial forms. Red Algae Red algae, or rhodophytes, are primarily multicellular, lack flagella, and range in size from microscopic, unicellular protists to large, multicellular forms grouped into the informal seaweed category. The red algae life cycle is an alternation of generations. Some species of red algae contain phycoerythrins, photosynthetic accessory pigments that are red in color and. | A: archaeplastida. |
If a machine only changes the direction of a force without changing the ratio of the output/input forces, then what is its associated mechanical advantage?
Here are the choices:
A. 1
B. 2
C. 4
D. 1.5 | For machines that change only the direction of the force, such as the rope systems on flagpoles, the output force is the same as the input force. Therefore, the mechanical advantage is equal to 1. | A: 1. |
What is an advantage of brightly colored fruits?
Here are the choices:
A. dyes for clothing
B. warning of poisons
C. make pretty paintings
D. attract animals to disperse their seeds | Brightly colored fruits attract animals that may disperse their seeds. It’s hard to miss the bright red apples on these trees. | D: attract animals to disperse their seeds. |
What is the apt term for the very slow movement of rock and soil down a hillside?
Here are the choices:
A. glide
B. creep
C. landslide
D. drop | Creep is the very slow movement of rock and soil down a hillside. Creep occurs so slowly you can’t see it happening. You can only see the effects of creep after years of movement ( Figure below ). The slowly moving ground causes trees, fence posts, and other structures on the surface to tilt downhill. | B: creep. |
The zeros at the end of a number are known as what?
Here are the choices:
A. trailing zeros
B. rest zeros
C. remaining zeros
D. edge zeros | Trailing zeros, which are zeros at the end of a number, are significant only if the number has a decimal point. Thus, in 1,500, the two trailing zeros are not. | A: trailing zeros. |
Does water get colder or warmer the deeper you go?
Here are the choices:
A. colder
B. warmer
C. neither
D. colder, than warmer | Water also gets colder as you go deeper. The weight of the water pressing down from above increases as well. At great depths, life becomes very difficult. The pressure is so great that only specially adapted creatures can live there. | A: colder. |
Many transition metals and their compounds are used as what?
Here are the choices:
A. sealants
B. insulators
C. catalysts
D. bases | Many transition metals and their compounds are used as catalysts. Given MnO 2, FeCl3, Pt, and Ni, which would you select for each purpose and why?. | C: catalysts. |
What do willow trees produce to kill bacteria?
Here are the choices:
A. Posion
B. bacterial acid
C. facultative acid
D. salicylic acid | Many plants also produce hormones and toxins to fight pathogens. For example, willow trees, like the one in Figure below , produce salicylic acid to kill bacteria. The same compound is used in many acne products for the same reason. | D: salicylic acid. |
What do decomposers release once they have broken down the dead organisms?
Here are the choices:
A. essential molecules
B. unusable molecules
C. inorganic molecules
D. organic molecules | Ecosystems require constant inputs of energy from sunlight or chemicals. Producers use energy and inorganic molecules to make food. Consumers take in food by eating producers or other living things. Decomposers break down dead organisms and other organic wastes and release inorganic molecules back to the environment. | C: inorganic molecules. |
Often determining the strength or intensity of a wave, this term is the distance from the equilibrium point of motion to either its lowest or highest point?
Here are the choices:
A. amplitude
B. peak
C. density
D. frequency | The amplitude , , is the distance from the equilibrium (or center) point of motion to either its lowest or highest point ( end points ). The amplitude, therefore, is half of the total distance covered by the oscillating object. The amplitude can vary in harmonic motion but is constant in SHM. The amplitude of a wave often determines its strength or intensity; the exact meaning of "strength" depends on the type of wave. For example, a sound wave with a large amplitude is a loud sound and a light wave with a large amplitude is very bright. | A: amplitude. |
Which type of muscle fiber can sustain long contractions?
Here are the choices:
A. intense fibers
B. direct fibers
C. slow fibers
D. fast fibres | C: slow fibers. | |
We would genetically be all the same if genes did not have different what?
Here are the choices:
A. atoms
B. alleles
C. bases
D. antigens | Chromosome, gene, locus and alleles are all related. What is the different between a gene and a locus? Between a gene and an allele? Chromosomes are composed of genes located at specific loci. And genes have different alleles. If genes did not have different alleles, we would genetically be all the same. What does that mean?. | B: alleles. |
Thylakoid membranes contain molecules of what green pigment used in photosynthesis?
Here are the choices:
A. copper
B. sodium
C. carbonate
D. chlorophyll | The structure of a chloroplast shows how membrane and molecular architecture helps life processes. A chloroplast consists of thylakoid membranes surrounded by stroma. The thylakoids stack on top of each other, like a stack of pancakes. The thylakoid stacks arrange chlorophyll, accessory pigment molecules, and photosynthetic proteins to capture sunlight and allow a concentration of ions within the sacs. You can see the green color of the chlorophyll. You cannot see the electron carriers, sequenced within the sac membranes, but their arrangement helps harvest small amounts of energy from excited electrons. The thylakoid membranes contain molecules of the green pigment chlorophyll. | D: chlorophyll. |
What is the name for a way of learning that involves reward or punishment?
Here are the choices:
A. subjective
B. objective
C. conditioning
D. instinct | Conditioning is a way of learning that involves a reward or punishment. Did you ever train a dog to fetch a ball or stick by rewarding it with treats? If you did, you were using conditioning. Another example of conditioning is shown in the video below; the rats have been taught to “play basketball” by being rewarded with food pellets. What do you think would happen if the rats were no longer rewarded for this behavior?. | C: conditioning. |
What scale measures the total energy released by an earthquake?
Here are the choices:
A. direct magnitude scale
B. moment radiation scale
C. moment magnitude scale
D. moment identification scale | The moment magnitude scale is the favored method of measuring earthquake magnitudes. It measures the total energy released by an earthquake. Moment magnitude is calculated by two things. One is the length of the fault break. The other is the distance the ground moves along the fault. | C: moment magnitude scale. |
All enzymes have an optimal temperature and what?
Here are the choices:
A. weight
B. ph
C. ions
D. shapes | B: ph. | |
When do homologous chromosomes form pairs?
Here are the choices:
A. mitosis
B. transcripton
C. metathesis
D. meiosis | When homologous chromosomes form pairs during prophase I of meiosis I, crossing-over can occur. Crossing-over is the exchange of genetic material between non-sister chromatids of homologous chromosomes. It results in new combinations of genes on each chromosome. | D: meiosis. |
What forms when the metal sodium gives up an electron to the nonmetal chlorine?
Here are the choices:
A. hydrogen bond
B. van der waals force
C. an ionic bond
D. covalent bond | An ionic bond forms when the metal sodium gives up an electron to the nonmetal chlorine. | C: an ionic bond. |
What type of gas is produced by alcoholic fermentation of the glucose in corn or other plants?
Here are the choices:
A. isopropyl
B. ethyl
C. methanol
D. ethanol | Have your parents ever put corn in the gas tank of their car? They did if they used gas containing ethanol. Ethanol is produced by alcoholic fermentation of the glucose in corn or other plants. This type of fermentation also explains why bread dough rises. Yeasts in bread dough use alcoholic fermentation and produce carbon dioxide gas. The gas forms bubbles in the dough, which cause the dough to expand. The bubbles also leave small holes in the bread after it bakes, making the bread light and fluffy. Do you see the small holes in the slice of bread in Figure below ?. | D: ethanol. |
What type of transport is vesicle transport considered to be?
Here are the choices:
A. intercellular transport
B. passive transport
C. active transport
D. catalyst | Some molecules, such as proteins, are too large to pass through the plasma membrane, regardless of their concentration inside and outside the cell. Very large molecules cross the plasma membrane with a different sort of help, called vesicle transport . Vesicle transport requires energy, so it is also a form of active transport. There are two types of vesicle transport: endocytosis and exocytosis. Both types are shown in Figure below and described below. | C: active transport. |
Strong bands of dense, regular connective tissue that connect muscles to bones are called what?
Here are the choices:
A. tendons
B. veins
C. cartilage
D. membranes | 11.1 | Interactions of Skeletal Muscles, Their Fascicle Arrangement, and Their Lever Systems By the end of this section, you will be able to: • Compare and contrast agonist and antagonist muscles • Describe how fascicles are arranged within a skeletal muscle • Explain the major events of a skeletal muscle contraction within a muscle in generating force To move the skeleton, the tension created by the contraction of the fibers in most skeletal muscles is transferred to the tendons. The tendons are strong bands of dense, regular connective tissue that connect muscles to bones. The bone connection is why this muscle tissue is called skeletal muscle. | A: tendons. |
Homes and transportation use what percent of all energy in the u.s.?
Here are the choices:
A. fifteen
B. half (fifty)
C. forty
D. twenty five | About half the energy used in the U. S. is used in homes and for transportation. Businesses, stores, and industry use the other half. | B: half (fifty). |
What falls roughly in the middle of the electromagnetic spectrum, having shorter wavelengths and higher frequencies than microwaves, but not as short and high as x rays?
Here are the choices:
A. light
B. radio waves
C. gamma rays
D. ultraviolet light | Light includes infrared light, visible light, and ultraviolet light. As you can see from the Figure above , light falls roughly in the middle of the electromagnetic spectrum. It has shorter wavelengths and higher frequencies than microwaves, but not as short and high as X rays. | A: light. |
What are models good for?
Here are the choices:
A. they are independent variables
B. they give us an idea of what the real thing is like
C. they are identical to the real thing
D. they are expensive to make | A model serves a useful purpose – it gives us an idea of what the real thing is like. The model plane seen above has wings, a tail, and an engine just like the real thing. This model also has a propeller, as is the case with most small planes and some smaller passenger planes. However, the model is not the real thing. We certainly cannot fly people or cargo in the model (besides maybe a tiny mouse), but we can get some idea of what a real plane looks like and how it works. | B: they give us an idea of what the real thing is like. |
Explanations of some aspect of the natural world based on repeated observations are termed what?
Here are the choices:
A. scientific guesses
B. scientific theories
C. scientific insights
D. scientific thoughts | Scientific theories are explanations of some aspect of the natural world based on repeated observations. | B: scientific theories. |
What is found in abundance in the polar ice caps and under the surface of mars?
Here are the choices:
A. bacteria
B. fossils
C. carbon
D. water | There is a lot of water ice in the polar ice caps and under the surface of Mars. | D: water. |
What do nerve impulses travel along?
Here are the choices:
A. pores
B. membranes
C. axons
D. arteries | C: axons. | |
Cyanobacteria are bluish green in color because they contain what?
Here are the choices:
A. microbial
B. carbonate
C. chlorophyll
D. chloroplasts | Bacteria called cyanobacteria are very important. They are bluish green in color (see Figure below ) because they contain chlorophyll. They make food through photosynthesis and release oxygen into the air. These bacteria were probably responsible for adding oxygen to the air on early Earth. This changed the planet’s atmosphere. It also changed the direction of evolution. Ancient cyanobacteria also may have evolved into the chloroplasts of plant cells. | C: chlorophyll. |
How many miles is the distance between the earth and sun?
Here are the choices:
A. 91
B. 93
C. 82
D. 78 | The distance between the Earth and the Sun is about 93 million miles, or 150 million kilometers. Earth revolves around the Sun at an average speed of about 27 kilometers (17 miles) per second. Mercury and Venus are closer to the Sun, so they take shorter times to make one orbit. Mercury takes only about 88 Earth days to make one trip around the Sun. All of the other planets take longer amounts of time. The exact amount depends on the planet's distance from the Sun. Saturn takes more than 29 Earth years to make one revolution around the Sun. How old would you be if you were on Jupiter?. | B: 93. |
What is the dominant form of plant life in most terrestrial ecosystems, comprising about 90 percent of all plant species?
Here are the choices:
A. gymnosperms
B. pteridophytes
C. bryophytes
D. angiosperms | 26.3 Angiosperms Angiosperms are the dominant form of plant life in most terrestrial ecosystems, comprising about 90 percent of all plant species. Most crops and ornamental plants are angiosperms. Their success comes from two innovative structures that protect reproduction from variability in the environment: the flower and the fruit. Flowers were derived from modified leaves. The main parts of a flower are the sepals and petals, which protect the reproductive parts: the stamens and the carpels. The stamens produce the male gametes in pollen grains. The carpels contain the female gametes (the eggs inside. | D: angiosperms. |
What is the largest mammal on earth?
Here are the choices:
A. water buffalo
B. giraffe
C. tiger shark
D. blue whale | Biological organization exists at all levels in organisms. It can be seen at the smallest level, in the molecules that make up such compounds as DNA and proteins, to the largest level, in an organism such as a blue whale, the largest mammal on Earth. Similarly, single celled prokaryotes and eukaryotes show order in the way their cells are arranged. Single-celled organisms such as an amoeba are free-floating and independent-living. Their single-celled "bodies" are able to carry out all the processes of life such as metabolism and respiration without help from other cells. | D: blue whale. |
What are elements that generally do not conduct electricity?
Here are the choices:
A. metal
B. iron
C. nonmetals
D. copper | Nonmetals are elements that generally do not conduct electricity. They are one of three classes of elements (the other two classes are metals and metalloids. ) Nonmetals are the second largest of the three classes after metals. They are the elements located on the right side of the periodic table. | C: nonmetals. |
Superconductors expel a magnetic field from their interior. what is this phenomenon known as?
Here are the choices:
A. meissner effect
B. eibner effect
C. weissenberg effect
D. lauer effect | Summary Superconductors are solids that at low temperatures exhibit zero resistance to the flow of electrical current, a phenomenon known as superconductivity. The temperature at which the electrical resistance of a substance drops to zero is itssuperconducting transition temperature (Tc). Superconductors also expel a magnetic field from their interior, a phenomenon known as the Meissner effect. Superconductivity can be explained by the BCS theory, which says that electrons are able to travel through a solid with no resistance because they couple to form pairs of electrons (Cooper pairs). Hightemperature superconductors haveTc values greater than 30 K. | A: meissner effect. |
Continually increasing the pressure on the liquid will eventually cause the substance to do what?
Here are the choices:
A. solidify
B. erode
C. explode
D. transform | Start right above point on the temperature axis and follow the red line vertically. At very low pressure, the particles of the substance are far apart from one another and the substance is in the gas state. As the pressure is increased, the particles of the substance are forced closer and closer together. Eventually the particles are pushed so close together that attractive forces cause the substance to condense into the liquid state. Continually increasing the pressure on the liquid will eventually cause the substance to solidify. For the majority of substances, the solid state is denser than the liquid state and so putting a liquid under great pressure will cause it to turn into a solid. The line segment represents the process of sublimation, where the substance changes directly from a solid to a gas. At a sufficiently low pressure, the liquid phase does not exist. The point labeled is called the triple point . The triple point is the one condition of temperature and pressure where the solid, liquid, and vapor states of a substance can all coexist at equilibrium. | A: solidify. |
Hypersensitivity may refer to a maladaptive response of what system toward a harmless foreign substance?
Here are the choices:
A. System
B. brain
C. oxygen
D. immune | Hypersensitivities Maladaptive immune responses toward harmless foreign substances or self antigens that occur after tissue sensitization are termed hypersensitivities. The types of hypersensitivities include immediate, delayed, and autoimmunity. A large proportion of the population is affected by one or more types of hypersensitivity. Allergies The immune reaction that results from immediate hypersensitivities in which an antibody-mediated immune response occurs within minutes of exposure to a harmless antigen is called an allergy. In the United States, 20 percent of the population exhibits symptoms of allergy or asthma, whereas 55 percent test positive against one or more allergens. Upon initial exposure to a potential allergen, an allergic individual synthesizes antibodies of the IgE class via the typical process of APCs presenting processed antigen to TH cells that stimulate B cells to produce IgE. This class of antibodies also mediates the immune response to parasitic worms. The constant domain of the IgE molecules interact with mast cells embedded in connective tissues. This process primes, or sensitizes, the tissue. Upon subsequent exposure to the same allergen, IgE molecules on mast cells bind the antigen via their variable domains and stimulate the mast cell to release the modified amino acids histamine and serotonin; these chemical mediators then recruit eosinophils which mediate allergic responses. Figure 42.26 shows an example of an allergic response to ragweed pollen. The effects of an allergic reaction range from mild. | D: immune. |
Similarity that results from common ancestry is known as what?
Here are the choices:
A. homology
B. heterogeny
C. affinity
D. duality | A: homology. | |
We all start as a single cell and soon grow into what?
Here are the choices:
A. nucleus
B. egg
C. embryo
D. uterus | We all start as a single cell and soon grow into an embryo. Notice the remarkable details beginning to form. The eyes, backbone, and limb buds are obvious. Think about the amazing complexity that must be going on inside the embryo, and the tremendous amount of growth and development still to come. So, yes, at one time we all looked similar. | C: embryo. |
Which acid contains only one ionizable hydrogen?
Here are the choices:
A. amino acid
B. lactic acid
C. citric acid
D. monoprotic acid | A monoprotic acid is an acid that contains only one ionizable hydrogen. Hydrochloric acid and acetic acid are monoprotic acids. A polyprotic acid is an acid that contains multiple ionizable hydrogens. Most common polyprotic acids are either diprotic (such as H 2 SO 4 ) or triprotic (such as H 3 PO 4 ). | D: monoprotic acid. |
The epidermis is made of which closely packed cells?
Here are the choices:
A. nerve cells
B. epithelial cells
C. muscle cells
D. cancer cells | Figure 5.2 Layers of Skin The skin is composed of two main layers: the epidermis, made of closely packed epithelial cells, and the dermis, made of dense, irregular connective tissue that houses blood vessels, hair follicles, sweat glands, and other structures. Beneath the dermis lies the hypodermis, which is composed mainly of loose connective and fatty tissues. | B: epithelial cells. |
What is a double membrane of the nucleus that encloses the genetic material?
Here are the choices:
A. nuclear enevelope
B. cell membrane
C. nuclear wall
D. cell wall | The nuclear envelope is a double membrane of the nucleus that encloses the genetic material. It separates the contents of the nucleus from the cytoplasm. The nuclear envelope is made of two lipid bilayers, an inner membrane and an outer membrane. The outer membrane is continuous with the rough endoplasmic reticulum. Many tiny holes called nuclear pores are found in the nuclear envelope. These nuclear pores help to regulate the exchange of materials (such as RNA and proteins) between the nucleus and the cytoplasm. | A: nuclear enevelope. |
What effect does changing temperature have on a system at equilibrium?
Here are the choices:
A. movement
B. energy
C. the height
D. stress | Increasing or decreasing the temperature of a system at equilibrium is also a stress to the system. The equation for the Haber-Bosch process is written again below, as a thermochemical equation. | D: stress. |
What type of cancer can the use of tanning beds lead to?
Here are the choices:
A. brain cancer
B. breast cancer
C. skin cancer
D. tissue cancer | You can reduce your risk of developing cancer by staying away from certain hazards. For example, the use of tanning beds can lead to skin cancer. | C: skin cancer. |
Organisms tend to be larger in size at higher what levels?
Here are the choices:
A. benthic
B. proteolytic
C. Secondary Layer
D. trophic | With less energy at higher trophic levels, there are usually fewer organisms as well. Organisms tend to be larger in size at higher trophic levels, but their smaller numbers result in less biomass. Biomass is the total mass of organisms at a trophic level. The decrease in biomass from lower to higher levels is also represented by Figure above . | D: trophic. |
A major step in animal evolution was the evolution of what rigid rod that runs the length of the body?
Here are the choices:
A. mitochondria
B. limbic system
C. endoderm
D. notochord | Another major step in animal evolution was the evolution of a notochord. A notochord is a rigid rod that runs the length of the body. It supports the body and gives it shape (see Figure below ). It also provides a place for muscles to anchor, and counterbalances them when they contract. Animals with a notochord are called chordates. They also have a hollow nerve cord that runs along the top of the body. Gill slits and a tail are two other chordate features. Many modern chordates have some of these structures only as embryos. | D: notochord. |
What is the name of the process that refers to the balance or equilibrium within the cell or a body?
Here are the choices:
A. hypothesis
B. static
C. homeostasis
D. determinants | Homeostasis refers to the balance, or equilibrium within the cell or a body. It is an organism’s ability to keep a constant internal environment. Keeping a stable internal environment requires constant adjustments as conditions change inside and outside the cell. The adjusting of systems within a cell is called homeostatic regulation. Because the internal and external environments of a cell are constantly changing, adjustments must be made continuously to stay at or near the set point (the normal level or range). Homeostasis is a dynamic equilibrium rather than an unchanging state. The cellular processes discussed in this lesson all play an important role in homeostatic regulation. More concerning homeostasis will be presented in additional concepts. | C: homeostasis. |
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