questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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What may be lost when waves travel through matter, but not when they travel through space?
Here are the choices:
A. matter
B. frequency
C. energy
D. threshold | As you can see in the Figure above , the electric and magnetic fields that make up an electromagnetic wave are perpendicular (at right angles) to each other. Both fields are also perpendicular to the direction that the wave travels. Therefore, an electromagnetic wave is a transverse wave. However, unlike a mechanical transverse wave, which can only travel through matter, an electromagnetic transverse wave can travel through empty space. When waves travel through matter, they lose some energy to the matter as they pass through it. But when waves travel through space, no energy is lost. Therefore, electromagnetic waves don’t get weaker as they travel. However, the energy is “diluted” as it travels farther from its source because it spreads out over an ever-larger area. | C: energy. |
Where does mechanical digestion begin?
Here are the choices:
A. intestines
B. mouth
C. stomach
D. brain | The mouth also begins the process of mechanical digestion . Sharp teeth in the front of the mouth cut or tear food when you bite into it (see Figure below ). Broad teeth in the back of the mouth grind food when you chew. Food is easier to chew because it is moistened by saliva from the salivary glands. The tongue helps mix the food with saliva and also helps you swallow. After you swallow, the chewed food passes into the pharynx. | B: mouth. |
How does the sun generate energy?
Here are the choices:
A. nuclear fusion
B. matter multiplication
C. atomic division
D. certain fusion | Heat from a wood fire can boil a pot of water. If you put an egg in the pot, you can eat a hard boiled egg in 15 minutes (cool it down first!). The energy to cook the egg was stored in the wood. The wood got that energy from the Sun when it was part of a tree. The Sun generated the energy by nuclear fusion. You started the fire with a match. The head of the match stores energy as chemical energy. That energy lights the wood on fire. The fire burns as long as there is energy in the wood. Once the wood has burned up, there is no energy left in it. The fire goes out. | A: nuclear fusion. |
What stored form of energy is made up of glycerol and three fatty acid chains?
Here are the choices:
A. triglycerides
B. carbohydrates
C. hydrocarbons
D. particulates | Triglycerides are the main form of stored energy in animals. This type of lipid is commonly called fat. Triglycerides are composed of a glycerol and three fatty acid chains. An example is shown in Figure below . In humans, triglycerides are a mechanism for storing unused calories, and their high concentration in blood correlates with the consumption of excess starches and other carbohydrate-rich foods. | A: triglycerides. |
What do jellyfish give off to startle possible predators?
Here are the choices:
A. energy
B. light
C. electricity
D. plankton | Imagine scuba diving and coming upon a jellyfish. Would you be startled if the jellyfish suddenly started to glow with bright yellow light, like the jellyfish in the picture above? If so, then the jellyfish would have done its job. Jellyfish give off light to startle possible predators. The light they emit is visible light. | B: light. |
What is an example of a metaloid element?
Here are the choices:
A. silicon
B. fluorine
C. chlorine
D. argon | Most metalloids have some physical properties of metals and some physical properties of nonmetals. They fall between metals and nonmetals in their ability to conduct heat and electricity. They are shiny like metals but brittle like nonmetals. All exist as solids at room temperature. | A: silicon. |
Scientists use a quantity called __________ as a measure of disorder, or randomness.
Here are the choices:
A. chance level
B. entropy
C. vector count
D. motion | B: entropy. | |
Niche refers to the role a species plays in what?
Here are the choices:
A. the ecosystem
B. migration
C. the habitat
D. reproduction | The role a species plays in the ecosystem is called its niche. | A: the ecosystem. |
An irreversible increase in size is known as?
Here are the choices:
A. strength
B. volume
C. mass
D. growth | D: growth. | |
Bacterial contamination of foods can lead to digestive problems, an illness known as what?
Here are the choices:
A. headache
B. food poisoning
C. acid reflux
D. ulcers | Bacterial contamination of foods can lead to digestive problems, an illness known as food poisoning . Raw eggs and undercooked meats commonly carry the bacteria that can cause food poisoning. Food poisoning can be prevented by cooking meat thoroughly, which kills most microbes, and washing surfaces that have been in contact with raw meat. Washing your hands before and after handling food also helps prevent contamination. | B: food poisoning. |
All combustion reactions are what type of reactions?
Here are the choices:
A. geothermal
B. flammable
C. reversible
D. exothermic | All combustion reactions are exothermic reactions. During a combustion reaction, a substance burns as it combines with oxygen. When substances burn, they usually give off energy as heat and light. Look at the big bonfire in the Figure below . The combustion of wood is an exothermic reaction that releases a lot of energy as heat and light. You can see the light energy the fire is giving off. If you were standing near the fire, you would also feel its heat. | D: exothermic. |
What produces microspores that develop into pollen grains containing male gametophytes?
Here are the choices:
A. stems
B. leaves
C. stamens
D. petals | C: stamens. | |
When a star's core collapses inward while the outer layers spread and cool, what "colorful" celestial body forms?
Here are the choices:
A. red giant
B. white giant
C. blue giant
D. green giant | Eventually a main sequence star will use up all of its hydrogen. It then starts to fuse helium atoms into larger elements like carbon. At this time, the star’s core will collapse inward. The star's outer layers will spread out and cool. The result is a larger star that is cooler on the surface, and red in color. The star is now a red giant . | A: red giant. |
Timber, obtained from trees that can be replanted to replace those that are cut down, is an example of what type of resource?
Here are the choices:
A. fossil fuel
B. renewable
C. mineral
D. nonrenewable | Renewable resources can be renewed as they are used. An example is timber, which comes from trees. New trees can be planted to replace those that are cut down. Sunlight is a renewable resource. It seems we will never run out of that!. | B: renewable. |
What type of blood does the right side of the heart collect and then pump to the lungs?
Here are the choices:
A. nitrogen-rich blood
B. nitrogen-poor blood
C. oxygen-poor blood
D. oxygen-rich blood | Blood flows through the heart in two separate loops, which are indicated by the arrows in Figure above. You can think of them as a "left side loop" and a "right side loop. " The right side of the heart collects oxygen-poor blood from the body and pumps the blood to the lungs. In the lungs, carbon dioxide is released and oxygen obtained by the blood. The left side of the heart carries the oxygen-rich blood back from the lungs and pumps it to the rest of the body. The blood delivers oxygen to the body's cells, returning the oxygen-poor blood back to the heart. | C: oxygen-poor blood. |
What elements have the highest attraction for electrons?
Here are the choices:
A. nonmetals
B. metals
C. carbons
D. gases | Nonmetals tend to gain electrons in chemical reactions and have a high attraction for electrons within a compound. The most reactive nonmetals reside in the upper right portion of the periodic table. Since the noble gases are a special group because of their lack of reactivity, the element fluorine is the most reactive nonmetal. It is not found in nature as a free element. Fluorine gas reacts explosively with many other elements and compounds and is considered to be one of the most dangerous known substances. | A: nonmetals. |
What is the layman's term for mammals raising their hair with tiny muscles in the skin, something that is automatic in humans sensing cold?
Here are the choices:
A. spine tingling
B. hypothermia
C. goosebumps
D. follicles | Goosebumps. Mammals raise their hair with tiny muscles in the skin. Even humans automatically contract these muscles when they are cold. They cause “goosebumps,” as shown here. | C: goosebumps. |
What are ring-shaped hydrocarbons called?
Here are the choices:
A. reverse hydrocarbons
B. cylindrical hydrocarbons
C. cyclic hydrocarbons
D. curved hydrocarbons | Hydrocarbons may form straight chains, branched chains, or rings. Ring-shaped hydrocarbons are called cyclic hydrocarbons. | C: cyclic hydrocarbons. |
What increases in processes in which solid or liquid reactants form gaseous products and when solid reactants form liquid products?
Here are the choices:
A. respiration
B. evaporation
C. entropy
D. glucose | For a given substance, the entropy of the liquid state is greater than the entropy of the solid state. Likewise, the entropy of the gas is greater than the entropy of the liquid. Therefore, entropy increases in processes in which solid or liquid reactants form gaseous products. Entropy also increases when solid reactants form liquid products. | C: entropy. |
How many pairs of legs do arachnids have?
Here are the choices:
A. 8
B. 6
C. 4
D. ten | Arachnids have four pairs of legs, specialized appendages, and a fused head and thorax. | C: 4. |
Besides the uppermost mantle, what else is the lithosphere composed of?
Here are the choices:
A. outer core
B. surface
C. inner core
D. crust | The lithosphere is composed of both the crust and the uppermost mantle. The lithosphere is a brittle, rigid solid. It is easily cracked or broken. | D: crust. |
What is another term for dry ice?
Here are the choices:
A. liquid nitrogen
B. carbonated ice
C. solid carbon dioxide
D. ice crystals | Solid carbon dioxide is also called dry ice. That’s because when it gets warmer and changes state, it doesn’t change to a liquid by melting. Instead, it changes directly to a gas without going through the liquid state. The process in which a solid changes directly to a gas is called sublimation . It occurs when energy is added to a solid such as dry ice. You can watch dry ice changing directly to a gas in the video at this URL: http://www. youtube. com/watch?v=J8mDGwf-5x0 . | C: solid carbon dioxide. |
Name the process that produces many copies of a certain gene.
Here are the choices:
A. gene multiplication
B. gene diversion
C. gene addition
D. gene cloning | D: gene cloning. | |
Rupture or blockage of arteries in the head is the usual cause of what condition?
Here are the choices:
A. migraine headache
B. stroke
C. heart attack
D. heart disease | B: stroke. | |
What type of lines run next to each other?
Here are the choices:
A. fault lines
B. crater lines
C. perpendicular lines
D. contour lines | Contour lines run next to each other. Each contour line is separated by a constant difference in elevation, usually noted on the map. | D: contour lines. |
What type of light sensing organs do scaophopoda have?
Here are the choices:
A. cilia
B. antennae
C. setae
D. radula | Members of class Scaphopoda (“boat feet”) are known colloquially as “tusk shells” or “tooth shells,” as evident when examining Dentalium, one of the few remaining scaphopod genera (Figure 28.27). Scaphopods are usually buried in sand with the anterior opening exposed to water. These animals bear a single conical shell, which has both ends open. The head is rudimentary and protrudes out of the posterior end of the shell. These animals do not possess eyes, but they have a radula, as well as a foot modified into tentacles with a bulbous end, known as captaculae. Captaculae serve to catch and manipulate prey. Ctenidia are absent in these animals. | D: radula. |
What kind of cleavage do mammalian eggs exhibit?
Here are the choices:
A. Meroblastic
B. cocklebur
C. spicule
D. holoblastic | D: holoblastic. | |
What is the name of the process for delivering water to crops?
Here are the choices:
A. reclamation
B. bilge
C. drainage
D. irrigation | Many crops are grown where there isn’t enough rainfall for plants to thrive. For example, crops are grown in deserts of the American Southwest. How is this possible? The answer is irrigation. Irrigation is any way of providing extra water to plants. Most of the water used in agriculture is used for irrigation. Livestock also use water, but they use much less. | D: irrigation. |
What is the process in which a liquid boils and changes to a gas?
Here are the choices:
A. melting
B. sublimation
C. vaporization
D. freezing | The process in which a liquid boils and changes to a gas is called vaporization . The temperature at which a liquid boils is its boiling point. The boiling point of water is 100°C (212°F). Other types of matter may have higher or lower boiling points. For example, the boiling point of table salt is 1413°C. The boiling point of nitrogen is -196°C. | C: vaporization. |
What are the two most common common ways that brain and spinal cord injuries occur?
Here are the choices:
A. sports and household accidents
B. falls and surgical error
C. car crashes and athletic activities
D. car crashes and falls | Brain and spinal cord injuries most commonly occur because of car crashes or athletic activities. Fortunately, many injuries can be prevented by wearing seat belts and safety helmets (see Figure below ). Avoiding unnecessary risks, such as doing stunts on a bike or diving into shallow water, can also reduce the chances of brain and spinal cord injuries. | C: car crashes and athletic activities. |
What is the largest planet in the solar system?
Here are the choices:
A. jupiter
B. mars
C. pluto
D. saturn | Jupiter is the largest planet in the solar system. It has bands of different colored clouds, and a long-lasting storm called the Great Red Spot. | A: jupiter. |
What are elements required in very small amounts?
Here are the choices:
A. minerals
B. macronutrients
C. micronutrients
D. pollutants | C: micronutrients. | |
What can be calculated by multiplying an object’s mass in kilograms (kg) by its velocity in meters per second (m/s)?
Here are the choices:
A. energy
B. ground speed
C. momentum
D. height | Momentum can be calculated by multiplying an object’s mass in kilograms (kg) by its velocity in meters per second (m/s). For example, assume that a golf ball has a mass of 0.05 kg. If the ball is traveling at a velocity of 50 m/s, its momentum is:. | C: momentum. |
What will happen to a rock when it's under tremendous stress?
Here are the choices:
A. it will fracture
B. it will slow
C. it will rebound
D. it will solidify | A rock under enough stress will fracture. There may or may not be movement along the fracture. If there is not movement, the fracture is a joint. If there is movement, the fracture is a fault. | A: it will fracture. |
Very large stars eventually become what extremely dense space regions, which are so dense that no light can escape from them?
Here are the choices:
A. worm holes
B. dark matter
C. black holes
D. moons | The largest-mass stars become black holes . These extremely large stars end their life in the same way as a medium-mass star in that they become a supernova. After the outer layers are blown away in the supernova, however, the core of the star shrinks down in volume but still has a huge mass. The density of this object is extremely high, even denser than neutron stars. This dense object will have a gravitational force so large that not even light can escape from the body. (A companion topic to this occurs in The General Theory of Relativity where we see than extremely strong gravitational attraction can even attract light. ) These objects appear black because light cannot leave them, that is, they pull all light back to their surface. Black holes capture everything nearby due to their massive gravity and so they grow in size. Black holes are a common topic for science fiction but keep in mind, they are simply a very dense ball of matter with intense gravitational attraction. | C: black holes. |
Which theory suggests plant species richness increases with island size?
Here are the choices:
A. island ecosystem model
B. island symbolic model
C. island equilibrium model
D. island biology model | C: island equilibrium model. | |
What state of hydrogen can be predicted based on the atoms to which it is bonded?
Here are the choices:
A. evaporation
B. oxidation
C. condensation
D. precipitation | The oxidation state of hydrogen can also be predicted based on the atoms to which it is bonded. As with other pure elements, hydrogen has an oxidation state of zero in H 2 . | B: oxidation. |
What occurs when there is little to no rain in a period of time?
Here are the choices:
A. floods
B. pollution
C. hurricanes
D. droughts | D: droughts. | |
At any specific time, the rate at which a reaction is proceeding is known as its what?
Here are the choices:
A. emitted rate
B. immediate rate
C. instantaneous rate
D. spontaneous rate | To obtain the tabulated results for this decomposition, the concentration of hydrogen peroxide was measured every 6 hours over the course of a day at a constant temperature of 40 °C. Reaction rates were computed for each time interval by dividing the change in concentration by the corresponding time increment, as shown here for the first 6-hour period: −Δ[H 2 O 2] −(0.500 mol/L − 1.000 mol/L) = = 0.0833 mol L −1 h −1 Δt (6.00 h − 0.00 h) Notice that the reaction rates vary with time, decreasing as the reaction proceeds. Results for the last 6-hour period yield a reaction rate of: −Δ[H 2 O 2] −(0.0625 mol/L − 0.125 mol/L) = = 0.0104 mol L −1 h −1 Δt (24.00 h − 18.00 h) This behavior indicates the reaction continually slows with time. Using the concentrations at the beginning and end of a time period over which the reaction rate is changing results in the calculation of an average rate for the reaction over this time interval. At any specific time, the rate at which a reaction is proceeding is known as its instantaneous rate. The instantaneous rate of a reaction at “time zero,” when the reaction commences, is its initial rate. Consider the analogy of a car slowing down as it approaches a stop sign. The vehicle’s initial rate—analogous to the beginning of a chemical reaction—would be the speedometer reading at the moment the driver begins pressing the brakes (t0). A few moments later, the instantaneous rate at a specific moment—call it t1—would be somewhat slower, as indicated by the speedometer reading at that point in time. As time passes, the instantaneous rate will continue to fall until it reaches zero, when the car (or reaction) stops. Unlike instantaneous speed, the car’s average speed is not indicated by the speedometer; but it can be calculated as the ratio of the distance traveled to the time required to bring the vehicle to a complete stop (Δt). Like the decelerating car, the average rate of a chemical reaction will fall somewhere between its initial and final rates. The instantaneous rate of a reaction may be determined one of two ways. If experimental conditions permit the measurement of concentration changes over very short time intervals, then average rates computed as described earlier provide reasonably good approximations of instantaneous rates. Alternatively, a graphical procedure may be used that, in effect, yields the results that would be obtained if short time interval measurements were possible. If we plot the concentration of hydrogen peroxide against time, the instantaneous rate of decomposition of H2O2 at any time t is given by the slope of a straight line that is tangent to the curve at that time (Figure 12.3). We can use calculus to evaluating the slopes of such tangent lines, but the procedure for doing so is beyond the scope of this chapter. | C: instantaneous rate. |
The skin is a familiar organ made of what kind of tissue?
Here are the choices:
A. epithelial tissue
B. recurrent tissue
C. aberrant tissue
D. innate tissue | The skin is a familiar organ made of epithelial tissue. | A: epithelial tissue. |
Evolution that occurs over a short period of time is known as what?
Here are the choices:
A. relatedness
B. short term evolution
C. pseudoevolution
D. microevolution | Evolution that occurs over a short period of time is known as microevolution . It might take place in just a couple of generations. This scale of evolution occurs at the level of the population. The Grants observed evolution at this scale in populations of Darwin’s finches. Beak size in finch populations changed in just two years because of a serious drought. | D: microevolution. |
What do osteoblasts secrete that mineralizes to become bone matrix?
Here are the choices:
A. collagen
B. carbon
C. calcium
D. spongin | Osteoblasts make new bone cells and secrete collagen that mineralizes to become bone matrix. They are responsible for bone growth and the uptake of minerals from the blood. | A: collagen. |
Atoms that have gained electrons and become negatively charged are called what?
Here are the choices:
A. cations
B. anions
C. negative ions
D. negative atoms | Changes to the nucleus of an atom require tremendous amounts of energy, so protons are not easily gained or lost by atoms. Electrons, on the other hand, are held fairly loosely and can often be removed quite easily. When an object loses some electrons, the remaining object is now positively charged because it has an excess of protons. The electrons may either remain free or may attach to another object. In that case, the extra electrons cause that object to become negatively charged. Atoms that have lost electrons and become positively charged are called positive ions, and atoms that have gained electrons and become negatively charged are called negative ions . | C: negative ions. |
Snakes are which type of animal?
Here are the choices:
A. carnivorous
B. herbivorous
C. vegivors
D. omnivores | All snakes are strictly carnivorous, eating small animals including lizards, other snakes, small mammals, birds, eggs, fish, snails, or insects. Because snakes cannot bite or tear their food to pieces, prey must be swallowed whole. Therefore, the body size of a snake has a major influence on its eating habits. A snake can usually estimate in advance if a prey is too large. | A: carnivorous. |
Cancer occurs most often in adults over what age?
Here are the choices:
A. seventy
B. thirty
C. twenty
D. fifty | Cancer occurs most often in adults, especially adults over the age of 50. The most common types of cancer in adults differ between males and females. | D: fifty. |
Mammals are either herbivores, carnivores or what?
Here are the choices:
A. nematodes
B. vegetarians
C. decomposers
D. omnivores | Some mammals are strictly herbivores or strictly carnivores . However, most mammals will eat other foods if necessary. Some mammals are omnivores . They routinely eat a variety of both plant and animal foods. Most mammals also feed on a variety of other species. The few exceptions include koalas, which feed only on eucalyptus plants, and giant pandas, which feed only on bamboo. Types of mammalian diets and examples of mammals that eat them are given in Table below . How would you classify your own diet?. | D: omnivores. |
What paired human organs play a vital role in maintaining homeostasis?
Here are the choices:
A. eyes
B. ears
C. kidneys
D. lungs | The kidneys ( Figure below ) are important organs in maintaining homeostasis , the ability of the body to maintain a stable internal environment despite a changing environment. Kidneys perform a number of homeostatic functions. | C: kidneys. |
What is the process in which glucose is made using energy in light called?
Here are the choices:
A. photosynthesis
B. glucosynthesis
C. gluconeogenesis
D. photogenesis | What is the source of glucose for living things? It is made by plants and certain other organisms. The process in which glucose is made using energy in light is photosynthesis . This process requires carbon dioxide and water. It produces oxygen in addition to glucose. | A: photosynthesis. |
What zone is outside the radiative zone?
Here are the choices:
A. convection zone
B. activation zone
C. peripheral zone
D. diffusion zone | The convection zone is where convection takes place. It is located outward from the radiative zone. | A: convection zone. |
What do you call the temperature at which a liquid boils and starts changing to a gas?
Here are the choices:
A. boiling point
B. vapor point
C. melting point
D. transformation point | The temperature at which a liquid boils and starts changing to a gas is called its boiling point. The boiling point of pure water is 100°C. | A: boiling point. |
The distinctive appearance of what tissue is due to polysaccharides called chondroitin sulfates?
Here are the choices:
A. bone
B. membrane
C. cartilage
D. collagen | Cartilage The distinctive appearance of cartilage is due to polysaccharides called chondroitin sulfates, which bind with ground substance proteins to form proteoglycans. Embedded within the cartilage matrix are chondrocytes, or cartilage cells, and the space they occupy are called lacunae (singular = lacuna). A layer of dense irregular connective tissue, the perichondrium, encapsulates the cartilage. Cartilaginous tissue is avascular, thus all nutrients need to diffuse through the matrix to reach the chondrocytes. This is a factor contributing to the very slow healing of cartilaginous tissues. The three main types of cartilage tissue are hyaline cartilage, fibrocartilage, and elastic cartilage (Figure 4.16). Hyaline cartilage, the most common type of cartilage in the body, consists of short and dispersed collagen fibers and contains large amounts of proteoglycans. Under the microscope, tissue samples appear clear. The surface of hyaline cartilage is smooth. Both strong and flexible, it is found in the rib cage and nose and covers bones where they meet to form moveable joints. It makes up a template of the embryonic skeleton before bone formation. A plate of hyaline cartilage at the ends of bone allows continued growth until adulthood. Fibrocartilage is tough because it has thick bundles of collagen fibers dispersed through its matrix. The knee and jaw joints and the the intervertebral discs are examples of fibrocartilage. Elastic cartilage contains elastic fibers as well as collagen and proteoglycans. This tissue gives rigid support as well as elasticity. Tug gently at your ear lobes, and notice that the lobes return to their initial shape. The external ear contains elastic cartilage. | C: cartilage. |
In the humid subtropical climate, summers are ____ but winters are very cold.
Here are the choices:
A. dry
B. long
C. wet
D. windy | In the humid subtropical climate, summers are wet but winters are very cold. | C: wet. |
What are found primarily in lines around the edges of some continents?
Here are the choices:
A. glaciers
B. Reefs
C. volcanoes
D. earthquakes | When earthquake epicenters are put on a map, they outline the plates . This is because the earthquakes where the plates come into contact with each other. Earthquakes are found primarily in lines around the edges of some continents. They are also found through the centers of some oceans. Some occur in patches in some land areas. | D: earthquakes. |
What is another name for trisomy 21?
Here are the choices:
A. cystic fibrosis
B. down syndrome
C. Fragile X
D. Tay-Sachs Disease | B: down syndrome. | |
Which part of the brain regulates the rate of breathing?
Here are the choices:
A. brain stem
B. brain uptake
C. brain stem
D. brain charge | The rate of breathing is regulated by the brain stem. It monitors the level of carbon dioxide in the blood and triggers faster or slower breathing as needed to keep the level within a narrow range. | A: brain stem. |
Light with the longest wavelengths is called what?
Here are the choices:
A. infrared light
B. visible light
C. X-rays
D. UV light | Light with the longest wavelengths is called infrared light . The term infrared means “below red. ” Infrared light is the range of light waves that have longer wavelengths and lower frequencies than red light in the visible range of light waves. The sun gives off infrared light as do flames and living things. You can’t see infrared light waves, but you can feel them as heat. But infrared cameras and night vision goggles can detect infrared light waves and convert them to visible images. For a deeper understanding of infrared light, watch the video at this URL: http://www. youtube. com/watch?v=2--0q0XlQJ0 . | A: infrared light. |
Which gas do people exhale during each breath?
Here are the choices:
A. carbon monoxide
B. nitrogen
C. oxygen
D. carbon dioxide | What is this strange-looking object? Can you guess what it is? It’s a model of a certain type of matter. Some types of matter are elements, or pure substances that cannot be broken down into simpler substances. Many other types of matter are compounds. The model above represents a compound. The compound it represents is carbon dioxide, a gas you exhale each time you breathe. | D: carbon dioxide. |
Nonvascular plants such as liverworts, hornworts, and mosses lack what three typical plant features?
Here are the choices:
A. flowers, leaves, bark
B. chloroplasts, stems, flowers
C. roots, leaves, chloroplasts
D. roots, stems, leaves | Nonvascular plants include liverworts, hornworts, and mosses. They lack roots, stems, and leaves. | D: roots, stems, leaves. |
Much of the iron produced is refined and converted into what?
Here are the choices:
A. sugar
B. plastic
C. steel
D. wood | Much of the iron produced is refined and converted into steel. Steel is made from iron by removing impurities and adding substances such as manganese, chromium, nickel, tungsten, molybdenum, and vanadium to produce alloys with properties that make the material suitable for specific uses. Most steels also contain small but definite percentages of carbon (0.04%–2.5%). However, a large part of the carbon contained in iron must be removed in the manufacture of steel; otherwise, the excess carbon would make the iron brittle. | C: steel. |
What can be formed by converging light rays behind a lens, onto a piece of film?
Here are the choices:
A. a mirror
B. a prism
C. a kaleidoscope
D. a photograph | When light rays converge behind a lens, a real image is formed. Real images are useful in that you can place photographic film at the physical location of the real image, expose the film to the light, and make a two-dimensional representation of the world, a photograph. | D: a photograph. |
What is the star-like structure inside the paramecia?
Here are the choices:
A. the contractile vacuole
B. the elongated vacuole
C. the baré vacuole
D. the reflex vacuole | The contractile vacuole is the star-like structure within the paramecia. | A: the contractile vacuole. |
What is the study of the chemical elements necessary for plant growth called?
Here are the choices:
A. plant nutrition
B. photosynthesis
C. plant propagation
D. phototropism | A: plant nutrition. | |
Both alpha and beta decay change the number of what in an atom's nucleus?
Here are the choices:
A. neutrons
B. Gamma decay
C. protons
D. electrons | Both alpha and beta decay change the number of protons in an atom’s nucleus, thereby changing the atom to a different element. In alpha decay, the nucleus loses two protons. In beta decay, the nucleus either loses a proton or gains a proton. In gamma decay, no change in proton number occurs, so the atom does not become a different element. | C: protons. |
What types of living things are divided into nonvascular and vascular groupings?
Here are the choices:
A. organs
B. animals
C. plants
D. mammals | The most basic division of modern plants is between nonvascular and vascular plants. Vascular plants are further divided into those that reproduce without seeds and those that reproduce with seeds. Seed plants, in turn, are divided into those that produce naked seeds in cones and those that produce seeds in the ovaries of flowers. | C: plants. |
What can exposure to chemical or biological agents cause later in life?
Here are the choices:
A. adaptation
B. an acquired immunodeficiency
C. spontaneous mutation
D. regression | B: an acquired immunodeficiency. | |
What direction are sediments deposited?
Here are the choices:
A. horizontally
B. diagonally
C. magnetic poles
D. vertically | Sediments are deposited horizontally so sedimentary rock layers are originally horizontal. | A: horizontally. |
When the air temperature reaches the dew point, water vapor starts to do what?
Here are the choices:
A. germinate
B. dissipate
C. condense
D. evaporate | A: When air temperature reaches the dew point, water vapor starts condensing. It may form dew (as on the spider web in the opening image), clouds, or fog. Dew forms on solid objects on the ground. Clouds form on tiny particles in the air high above the ground. Fog is a cloud that forms on tiny particles in the air close to the ground. | C: condense. |
What do you call the metal elements listed below the periodic table?
Here are the choices:
A. process metals
B. transition metals
C. shift metals
D. rare metals | Transition metals include the elements that are placed below the periodic table. Those that follow lanthanum (La) are called lanthanides. They are all shiny, relatively reactive metals. Those that follow Actinium (Ac) are called actinides. They are all radioactive metals. This means they are unstable. They break down into different, more stable elements. You can read more about radioactive elements in the chapter Nuclear Chemistry . Many of the actinides do not occur in nature but are made in laboratories. | B: transition metals. |
Each silicon atom shares how many valence electrons with other silicon atoms in a crystal?
Here are the choices:
A. three
B. ten
C. five
D. four | Each silicon atom has four valence electrons it shares with other silicon atoms in a crystal. A semiconductor is formed by replacing a few silicon atoms with other atoms that have more or less valence electrons than silicon. | D: four. |
What is produced by the reaction of metal oxide with water?
Here are the choices:
A. soluble metal hydroxides
B. hydrogen gas
C. rust
D. heat energy | Hydroxides Hydroxides are compounds that contain the OH− ion. It is possible to prepare these compounds by two general types of reactions. Soluble metal hydroxides can be produced by the reaction of the metal or metal oxide with water. | A: soluble metal hydroxides. |
Which type of weathering causes changes int he rocks materials, chemical or mechanical?
Here are the choices:
A. mineral
B. nuclear
C. chemical
D. liquid | The original rock is the source of the inorganic portion of the soil. Mechanical weathering breaks rock into smaller pieces. Chemical reactions change the rock's minerals. | C: chemical. |
What type of rocks form from sediments that are cemented and compacted?
Here are the choices:
A. limestone
B. granite
C. sedimentary
D. crystalline | Sedimentary rocks form from sediments that are cemented and compacted. | C: sedimentary. |
What is the common term for solid carbon dioxide, which is used as a coolant?
Here are the choices:
A. liquid nitrogen
B. dry ice
C. antifreeze
D. blue ice | "Dry ice," or solid carbon dioxide, is a substance that sublimes at atmospheric pressures. Dry ice is very cold (−78°C) and so is used as a coolant for goods such as ice cream that must remain frozen during shipment. Because the dry ice sublimes rather than melting, there is no liquid mess associated with its change of state as the dry ice warms. As you may have seen in demonstrations, dry ice merely transforms from a solid to a cold, steamy looking gas. Ferrocene (an iron-containing compound) is usually purified by sublimation by gentle warming at atmospheric pressure. In the Figure below , you can see the reddish ferrocene crystals deposited on the outside of that tube. Deposition is the change of state from a gas to a solid. | B: dry ice. |
What is the most common type of joint in the human body?
Here are the choices:
A. proximal joints
B. movable joints
C. transverse joints
D. dorsal joints | Movable joints are also the most common type of joint in your body. Your fingers, toes, hips, elbows, and knees all provide examples of movable joints. The surfaces of bones at movable joints are covered with a smooth layer of cartilage. The cartilage reduces friction between the bones. Ligaments often cross a joint, holding two nones together. For example, there are numerous ligaments connecting the leg bones across the knee joint. | B: movable joints. |
What kind of relationship exists between living things that depend on the same resources?
Here are the choices:
A. symbiotic
B. parasitic
C. antagonistic
D. competition | Competition is a relationship between living things that depend on the same resources. | D: competition. |
Latitude plays an important role in determining what in a region?
Here are the choices:
A. migration
B. landscape
C. climate
D. drought | Major climate types are based on temperature and precipitation. Latitude plays an important role in determining the climate of a region. However, many other factors play a role in climate. Oceans and mountain ranges influence climate in the same ways worldwide ( Figure below ). You can see where the climate types are on the map, and then read about them below. | C: climate. |
A very small artery that leads to a capillary is known as what?
Here are the choices:
A. vein
B. capillary junction
C. arteriole
D. arterium | Arterioles An arteriole is a very small artery that leads to a capillary. Arterioles have the same three tunics as the larger vessels, but the thickness of each is greatly diminished. The critical endothelial lining of the tunica intima is intact. The tunica media is restricted to one or two smooth muscle cell layers in thickness. The tunica externa remains but is very thin (see Figure 20.4). With a lumen averaging 30 micrometers or less in diameter, arterioles are critical in slowing down—or resisting—blood flow and, thus, causing a substantial drop in blood pressure. Because of this, you may see them referred to as resistance vessels. The muscle fibers in arterioles are normally slightly contracted, causing arterioles to maintain a consistent muscle tone—in this case referred to as vascular tone—in a similar manner to the muscular tone of skeletal muscle. In reality, all blood vessels exhibit vascular tone due to the partial contraction of smooth muscle. The importance of the arterioles is that they will be the primary site of both resistance and regulation of blood pressure. The precise diameter of the lumen of an arteriole at any given moment is determined by neural and chemical controls, and vasoconstriction and vasodilation in the arterioles are the primary mechanisms for distribution of blood flow. | C: arteriole. |
What kind of systems use fluid to transmit pressure and increase force?
Here are the choices:
A. plumbing systems
B. thermal systems
C. hydraulic systems
D. electromagnetic systems | Hydraulic car lifts also use fluid to transmit pressure and increase force. The lifts are used to raise cars, which are very heavy, so mechanics can work on them from underneath. Controls in airplanes use fluids to transmit pressure and increase force so a flick of a switch can raise or lower heavy landing gear. To see animations of hydraulic systems such as these, go to URLs:. | C: hydraulic systems. |
What organ interprets what our sensory organs sense?
Here are the choices:
A. lungs
B. brain
C. thyroid
D. nerves | Sensory neurons in each sense organ receive stimuli, or messages from the environment that cause a response in the body. For example, sensory neurons in the eyes send messages to the brain about light. Sensory neurons in the skin send messages to the brain about touch. Our sense organs recognize sensations, but they don’t tell us what we are sensing. For example, when you breathe in chemicals given off by baking cookies, your nose does not tell you that you are smelling cookies. That’s your brain’s job. The sense organs send messages about sights, smells, and other stimuli to the brain ( Figure below ). The brain then reads the messages and tells you what they mean. A certain area of the brain receives and interprets information from each sense organ. For example, information from the nose is received and interpreted by the temporal lobe of the cerebrum. | B: brain. |
Gametes are products through meiosis in which organs?
Here are the choices:
A. hormones
B. cones
C. gonads
D. kidneys | At the end of meiosis, haploid cells are produced. These cells need to further develop into mature gametes capable of fertilization, a process called gametogenesis ( Figure below ). Animals produce gametes directly through meiosis in organs called gonads. Gametogenesis differs between the sexes. In the male, the production of mature sperm cells, or spermatogenesis , results in four haploid gametes, whereas, in the female, the production of a mature egg cell, oogenesis , results in just one mature gamete. | C: gonads. |
Haumea, which is the third brightest kuiper belt object has an odd oval shape which is probably caused by what?
Here are the choices:
A. unusually rapid rotation
B. extremely rapid rotation
C. particularly rapid rotation
D. Slow rotation | Haumea is the third-brightest Kuiper belt object. Haumea has two moons. Haumea's odd oval shape is probably caused by its extremely rapid rotation. It rotates in just less than 4 hours! Like other Kuiper belt objects, Haumea is covered by ice. Its density is similar to Earth’s Moon, at 2.6 – 3.3 g/cm 3 . This means that most of Haumea is rocky. | B: extremely rapid rotation. |
A changing magnetic field produces an electric current in what?
Here are the choices:
A. substance
B. a conductor
C. organ
D. matter | Law stating that a changing magnetic field produces an electric current in a conductor. | B: a conductor. |
What do plants do to prevent water loss at night?
Here are the choices:
A. open their petals
B. shed their petals
C. close their stems
D. close their leaves | Plants also detect and respond to the daily cycle of light and darkness. For example, some plants open their leaves during the day to collect sunlight and then close their leaves at night to prevent water loss. Environmental stimuli that indicate changing seasons trigger other responses. Many plants respond to the days growing shorter in the fall by going dormant . They suspend growth and development in order to survive the extreme cold and dryness of winter. Dormancy ensures that seeds will germinate and plants will grow only when conditions are favorable. | D: close their leaves. |
What term describes a colloidal dispersion of a liquid in either a liquid or a solid?
Here are the choices:
A. mix
B. suspension
C. compound
D. emulsion | An emulsion is a colloidal dispersion of a liquid in either a liquid or a solid. | D: emulsion. |
What evidence is there that mt. everest was once at the bottom of a sea?
Here are the choices:
A. fossils
B. corals
C. skulls
D. glaciers | Fossils of ocean animals are found at the top of Mt. Everest. Mt. Everest is the highest mountain on Earth. These fossils show that the area was once at the bottom of a sea. The seabed was later uplifted to form the Himalaya mountain range. An example is shown in the Figure below . | A: fossils. |
Because atoms have equal numbers of positive protons and negative electrons, what kind of electric charge do they possess?
Here are the choices:
A. neutral
B. none
C. negative
D. positive | Atoms have equal numbers of positive protons and negative electrons, so they are neutral in electric charge. | A: neutral. |
What is the term for interactions between individuals of different species over an extended period of time which impact the abundance and distribution of the associating populations?
Here are the choices:
A. cooperative evolution
B. symbiotic relationships
C. food chain
D. parasitic relationships | Symbiosis Symbiotic relationships, or symbioses (plural), are close interactions between individuals of different species over an extended period of time which impact the abundance and distribution of the associating populations. Most scientists accept this definition, but some restrict the term to only those species that are mutualistic, where both individuals benefit from the interaction. In this discussion, the broader definition will be used. Commensalism A commensal relationship occurs when one species benefits from the close, prolonged interaction, while the other neither benefits nor is harmed. Birds nesting in trees provide an example of a commensal relationship (Figure 45.25). The tree is not harmed by the presence of the nest among its branches. The nests are light and produce little strain on the structural integrity of the branch, and most of the leaves, which the tree uses to get energy by photosynthesis, are above the nest so they are unaffected. The bird, on the other hand, benefits greatly. If the bird had to nest in the open, its eggs and young would be vulnerable to predators. Another example of a commensal relationship is the clown fish and the sea anemone. The sea anemone is not harmed by the fish, and the fish benefits with protection from predators who would be stung upon nearing the sea anemone. | B: symbiotic relationships. |
Plane mirrors work because the light rays create what behind the mirror?
Here are the choices:
A. a virtual image
B. a virtual example
C. a mirror image
D. a entire image | The sketch below shows how we see an image in a plane mirror. Plane mirrors work because the light rays create a virtual image behind the mirror. Light rays from the object strike the mirror and reflect according to the law of reflection. When some of the light rays enter our eye, our eye and brain interpret these rays as having traveled in a straight line path. Therefore, our eye and brain track the light rays backward to a position from which they appear to have come. At this position, we see an image. | A: a virtual image. |
What do we call natural resources that are remade by natural processes as quickly as people use them?
Here are the choices:
A. geothermal
B. exotic
C. nonrenewable
D. renewable | Renewable resources are natural resources that are remade by natural processes as quickly as people use them. Examples of renewable resources include sunlight and wind. They are in no danger of being used up. Metals and some other minerals are considered renewable as well because they are not destroyed when they are used. Instead, they can be recycled and used over and over again. | D: renewable. |
What is the process of breaking down food into components the body can absorb called?
Here are the choices:
A. excretion
B. digestion
C. absorption
D. filtration | The digestive system has three main functions: digestion of food, absorption of nutrients, and elimination of solid food waste. Digestion is the process of breaking down food into components the body can absorb. It consists of two types of processes: mechanical digestion and chemical digestion. | B: digestion. |
What controls what moves inside and outside the cell?
Here are the choices:
A. nucleus
B. golgi apparatus
C. mitochondria
D. the plasma membrane | The plasma membrane controls what moves inside and outside the cell. | D: the plasma membrane. |
Yeasts are single-celled fungi. about 1,000 species are recognized, but the most common species is saccharomyces cerevisiae, which is used in this?
Here are the choices:
A. potatoes making
B. bread making
C. cookie making
D. cake making | Opening Essay Although yeast has been used for thousands of years, its true nature has been known only for the last two centuries. Yeasts are single-celled fungi. About 1,000 species are recognized, but the most common species is Saccharomyces cerevisiae, which is used in bread making. Other species are used for the fermentation of alcoholic beverages. Some species can cause infections in humans. Yeasts live primarily on sugars, such as glucose (C6H12O6). They convert glucose into carbon dioxide (CO2) and ethanol (C2H5OH) in a chemical transformation that is represented as follows:. | B: bread making. |
Another measure of the effectiveness of a machine is its what?
Here are the choices:
A. mechanical advantage
B. aesthetic effect
C. cost benefit
D. chemical advantage | Another measure of the effectiveness of a machine is its mechanical advantage. Mechanical advantage is the number of times a machine multiplies the input force. It can be calculated with the equation:. | A: mechanical advantage. |
What are biofilms resistant to many common forms of?
Here are the choices:
A. vaccination
B. assimilation
C. sterilization
D. termination | planktonic counterparts. Overall, biofilms are very difficult to destroy because they are resistant to many common forms of sterilization. | C: sterilization. |
Fractures and faults are terms you hear when talking about?
Here are the choices:
A. magnets
B. earthquakes
C. volcanoes
D. storms | Compare fractures and faults and define how they are related to earthquakes. | B: earthquakes. |
What are resources that can not be remade, or would take too long to remake to keep up wiht human use called?
Here are the choices:
A. nonrewable resources
B. photoreactive resources
C. green resources
D. renewable resources | Nonrenewable resources are natural resources that can’t be remade or else take too long to remake to keep up with human use. Examples of nonrenewable resources are coal, oil, and natural gas, all of which are fossil fuels. Fossil fuels form from the remains of plants and animals over hundreds of millions of years. We are using them up far faster than they can be replaced. At current rates of use, oil and natural gas will be used up in just a few decades, and coal will be used up in a couple of centuries. | A: nonrewable resources. |
Alkenes with the same atoms but different shapes are called what?
Here are the choices:
A. monomers
B. alcohols
C. isomers
D. isotopes | Alkenes can have different shapes. They can form straight chains, branched chains, or rings. Alkenes with the same atoms but different shapes are called isomers. Smaller alkenes have relatively high boiling and melting points, so they are gases at room temperature. Larger alkenes have lower boiling and melting points, so they are liquids or waxy solids at room temperature. | C: isomers. |
Which of the animals digest cellulose with the aid of methanogens?
Here are the choices:
A. apes
B. goats
C. cows
D. pigs | Stuart Chalmers. Cows digest cellulose with the aid of methanogens . CC BY 2.0. | C: cows. |
What is the major source of warmth for earth?
Here are the choices:
A. the sun
B. the Moon
C. equator
D. seasons | Earth is warmed by energy that radiates from the sun. Earth radiates some of the energy back into space. Greenhouse gases (GHGs) trap much of the re-radiated energy, causing an increase in the temperature of the atmosphere close to the surface. | A: the sun. |
Like a runner passing a baton, the transmission of nerve impulses between neurons depends on what?
Here are the choices:
A. neurotransmitters
B. receptors
C. axons
D. enzymes | The transmission of nerve impulses between neurons is like the passing of a baton between runners in a relay race. After the first runner races, she passes the baton to the second runner. Then the second runner takes over. Instead of a baton, a neuron passes neurotransmitters to the next neuron. | A: neurotransmitters. |
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