questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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When additional water is added to an aqueous solution, what happens to the concentration of that solution?
Here are the choices:
A. increases
B. no change
C. decreases
D. doubles | When additional water is added to an aqueous solution, the concentration of that solution decreases. This is because the number of moles of the solute does not change, while the volume of the solution increases. We can set up an equality between the moles of the solute before the dilution (1) and the moles of the solute after the dilution (2). | C: decreases. |
How many chambers does a mammalian heart have?
Here are the choices:
A. five
B. three
C. one
D. four | The four-chambered mammalian heart can pump blood in two different directions. The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart pumps blood containing oxygen to the rest of the body. Because of the dual pumping action of the heart, all of the blood going to body cells is rich in oxygen. | D: four. |
Meaning a disease that spreads from person to person, what term is synonymous with "contagious"?
Here are the choices:
A. harmless
B. benign
C. noncommunicable
D. infectious | Has this ever happened to you? A student sitting next to you in class has a cold. The other student is coughing and sneezing, but you feel fine. Two days later, you come down with a cold, too. Diseases like colds are contagious. Contagious diseases are also called infectious diseases. An infectious disease is a disease that spreads from person to person. | D: infectious. |
The common carotid artery gives rise to the external and internal carotid arteries. the external carotid artery remains superficial and gives rise to many arteries of this?
Here are the choices:
A. stomach
B. back
C. chest
D. head | Figure 20.26 Arteries Supplying the Head and Neck The common carotid artery gives rise to the external and internal carotid arteries. The external carotid artery remains superficial and gives rise to many arteries of the head. The internal carotid artery first forms the carotid sinus and then reaches the brain via the carotid canal and carotid foramen, emerging into the cranium via the foramen lacerum. The vertebral artery branches from the subclavian artery and passes through the transverse foramen in the cervical vertebrae, entering the base of the skull at the vertebral foramen. The subclavian artery continues toward the arm as the axillary artery. | D: head. |
What are resources that don't run out?
Here are the choices:
A. renewable resources
B. general resources
C. orbital resources
D. residual resources | 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! What are some other renewable resources?. | A: renewable resources. |
Maintaining a balance inside the body or cells of organisms is known as?
Here are the choices:
A. consciousness
B. homeostasis
C. equanimity
D. ketosis | When you are cold, what does your body do to keep warm? You shiver to warm up your body. When you are too warm, you sweat to release heat. When any living organism gets thrown off balance, its body or cells help it return to normal. In other words, living organisms have the ability to keep a stable internal environment. Maintaining a balance inside the body or cells of organisms is known as homeostasis . Like us, many animals have evolved behaviors that control their internal temperature. A lizard may stretch out on a sunny rock to increase its internal temperature, and a bird may fluff its feathers to stay warm ( Figure below ). | B: homeostasis. |
The ability to what is affected by the velocity, or speed, of the water?
Here are the choices:
A. construct
B. hinder
C. impede
D. erode | Moving water also picks up and carries particles of soil and rock. The ability to erode is affected by the velocity, or speed, of the water. The size of the eroded particles depends on the velocity of the water. Eventually, the water deposits the materials. As water slows, larger particles are deposited. As the water slows even more, smaller particles are deposited. The graph in Figure below shows how water velocity and particle size influence erosion and deposition. | D: erode. |
What is the process of isolating a specific gene and then making a copy of it for use in gene therapy?
Here are the choices:
A. attribute cloning
B. gene copying
C. gene cloning
D. gene treatment | Gene cloning is the process of isolating and making copies of a gene. This is useful for many purposes. For example, gene cloning might be used to isolate and make copies of a normal gene for gene therapy. Gene cloning involves four steps: isolation, ligation, transformation, and selection. You can watch an interactive animation about gene cloning at this link: http://www. teachersdomain. org/asset/biot09_int_geneclone/ . | C: gene cloning. |
The epochs of the universe are known back to very shortly after what 'explosive' event?
Here are the choices:
A. Biggest bang
B. major bang
C. big bang
D. Explosive bang | H0 = 20km/s ⋅ Mly. • Explanations of the large-scale characteristics of the universe are intimately tied to particle physics. • The dominance of matter over antimatter and the smoothness of the CMBR are two characteristics that are tied to particle physics. • The epochs of the universe are known back to very shortly after the Big Bang, based on known laws of physics. • The earliest epochs are tied to the unification of forces, with the electroweak epoch being partially understood, the GUT epoch being speculative, and the TOE epoch being highly speculative since it involves an unknown single superforce. • The transition from GUT to electroweak is called spontaneous symmetry breaking. It released energy that caused the inflationary scenario, which in turn explains the smoothness of the CMBR. | C: big bang. |
What is the term for a change in an object’s motion, which occurs whenever an object is acted upon by an unbalanced force?
Here are the choices:
A. inclination
B. rotation
C. compression
D. acceleration | A change in an object’s motion—such as Xander speeding up on his scooter—is called acceleration . Acceleration occurs whenever an object is acted upon by an unbalanced force. The greater the net force acting on the object, the greater its acceleration will be, but the mass of the object also affects its acceleration. The smaller its mass is, the greater its acceleration for a given amount of force. Newton’s second law of motion summarizes these relationships. According to this law, the acceleration of an object equals the net force acting on it divided by its mass. This can be represented by the equation:. | D: acceleration. |
All metabolic functions carried out by a prokaryote take place in the plasma membrane or where else?
Here are the choices:
A. Shell
B. mitochondrial
C. extracellular
D. cytosol | The bacterium in Figure above is a prokaryote. Prokaryotes are microscopic organisms that have neither a membrane-bound nucleus nor membrane-bound organelles. Some cell biologists consider the term "organelle" to describe membrane-bound structures only, whereas other cell biologists define organelles as discrete structures that have a specialized function. Prokaryotes have ribosomes, which are not surrounded by a membrane but do have a specialized function, and could therefore be considered organelles. All metabolic functions carried out by a prokaryote take place in the plasma membrane or the cytosol. | D: cytosol. |
How does burning matter affect its mass?
Here are the choices:
A. the mass remains the same
B. the mass decreases
C. the mass increases
D. the mass quadruples | Burning and other changes in matter do not destroy matter. The mass of matter is always the same before and after the changes occur. | A: the mass remains the same. |
What type of stratified deposit is formed where lakes are covered by ice in the winter?
Here are the choices:
A. varves
B. telomeres
C. tangles
D. glacier | Several types of stratified deposits form in glacial regions but are not formed directly by the ice. Varves form where lakes are covered by ice in the winter. Dark, fine-grained clays sink to the bottom of the lake in winter. Melting ice in the spring brings running water that deposits lighter colored sands. Each alternating dark/light layer represents one year of deposits. | A: varves. |
Where do greenhouse gases trap heat?
Here are the choices:
A. altitude
B. atmosphere
C. space
D. ground | We learned in the previous concept, "Scientific Explanations and Interpretations," that the average global temperature has been on the rise. Scientists know that carbon dioxide is a greenhouse gas . Greenhouse gases trap heat in the atmosphere. This leads us to a question:. | B: atmosphere. |
The hamstrings flex the leg, whereas the quadriceps femoris have what effect?
Here are the choices:
A. stabilize
B. no effect
C. contract
D. extend | The hamstrings flex the leg, whereas the quadriceps femoris extend it. | D: extend. |
Many ceramics are composed of what, which are salts containing anions composed of silicon and oxygen?
Here are the choices:
A. crystals
B. silicates
C. vinylates
D. soils | At 1600 °C, quartz melts to yield a viscous liquid. When the liquid cools, it does not crystallize readily but usually supercools and forms a glass, also called silica. The SiO4 tetrahedra in glassy silica have a random arrangement characteristic of supercooled liquids, and the glass has some very useful properties. Silica is highly transparent to both visible and ultraviolet light. For this reason, it is important in the manufacture of lamps that give radiation rich in ultraviolet light and in certain optical instruments that operate with ultraviolet light. The coefficient of expansion of silica glass is very low; therefore, rapid temperature changes do not cause it to fracture. CorningWare and other ceramic cookware contain amorphous silica. Silicates are salts containing anions composed of silicon and oxygen. In nearly all silicates, sp3-hybridized silicon atoms occur at the centers of tetrahedra with oxygen at the corners. There is a variation in the silicon-to-oxygen ratio that occurs because silicon-oxygen tetrahedra may exist as discrete, independent units or may share oxygen atoms at corners in a variety of ways. In addition, the presence of a variety of cations gives rise to the large number of silicate minerals. Many ceramics are composed of silicates. By including small amounts of other compounds, it is possible to modify the physical properties of the silicate materials to produce ceramics with useful characteristics. | B: silicates. |
Attaching strips of neutral metals that are higher in the activity series can protect a structure from what?
Here are the choices:
A. deoxidation
B. corrosion
C. weathering
D. diffusion | Attaching strips of neutral metals that are higher in the activity series can protect a structure from corrosion. | B: corrosion. |
Weight is a measure of what force pulling down on an object?
Here are the choices:
A. gravity
B. light
C. distortion
D. motion | Weight is a measure of the force of gravity pulling down on an object, whereas buoyant force pushes up on an object. Which force is greater determines whether an object sinks or floats. Look at the Figure below . On the left, the object’s weight is the same as the buoyant force acting on it, so the object floats. On the right, the object’s weight is greater than the buoyant force acting on it, so the object sinks. | A: gravity. |
What organ absorbs about 90 percent of the water you ingest?
Here are the choices:
A. lungs
B. skin
C. small intestine
D. large intestine | Absorption, Feces Formation, and Defecation The small intestine absorbs about 90 percent of the water you ingest (either as liquid or within solid food). The large intestine absorbs most of the remaining water, a process that converts the liquid chyme residue into semisolid feces (“stool”). Feces is composed of undigested food residues, unabsorbed digested substances, millions of bacteria, old epithelial cells from the GI mucosa, inorganic salts, and enough water to let it pass smoothly out of the body. Of every 500 mL (17 ounces) of food residue that enters the cecum each day, about 150 mL (5 ounces) become feces. Feces are eliminated through contractions of the rectal muscles. You help this process by a voluntary procedure called Valsalva’s maneuver, in which you increase intra-abdominal pressure by contracting your diaphragm and abdominal wall muscles, and closing your glottis. The process of defecation begins when mass movements force feces from the colon into the rectum, stretching the rectal wall and provoking the defecation reflex, which eliminates feces from the rectum. This parasympathetic reflex is mediated by the spinal cord. It contracts the sigmoid colon and rectum, relaxes the internal anal sphincter, and initially contracts the external anal sphincter. The presence of feces in the anal canal sends a signal to the brain, which gives you the choice of voluntarily opening the external anal sphincter (defecating) or keeping it temporarily closed. If you decide to delay defecation, it takes a few seconds for the reflex contractions to stop and the rectal walls to relax. The next mass movement will trigger additional defecation reflexes until you defecate. If defecation is delayed for an extended time, additional water is absorbed, making the feces firmer and potentially leading to constipation. On the other hand, if the waste matter moves too quickly through the intestines, not enough water is absorbed, and diarrhea can result. This can be caused by the ingestion of foodborne pathogens. In general, diet, health, and stress determine the frequency of bowel movements. The number of bowel movements varies greatly between individuals, ranging from two or three per day to three or four per week. | C: small intestine. |
In drosophila, gradients of morphogens encoded by maternal effect genes determine what?
Here are the choices:
A. cell mass
B. cells axes
C. body mass
D. body axes | D: body axes. | |
What features of a salamander's skin help protect itself from predators ?
Here are the choices:
A. thick and impenetrable
B. slimy and camouflaged
C. camouflaged and thin
D. brightly colored and poisonous | Salamanders have developed ways not to be eaten. Most salamanders have brightly colored, poisonous skin. The bold color tells predators not to eat the salamander. Many salamanders have glands on the back of the neck or on the tail that give off a poisonous or bad-tasting liquid. Some species can even shed their tail during an attack and grow a new one later. Some salamanders stand high on its legs and waves its tail to scare away danger. One particular salamander, the ribbed newt, has needle-like rib tips. It can squeeze its muscles to make the rib tips pierce through its skin and into its enemy, telling the predator to stay away, a feature unique among the animal kingdom. | D: brightly colored and poisonous. |
Precipitation maps show the amount of what in different areas?
Here are the choices:
A. population
B. geographical variety
C. heat
D. rainfall | Precipitation maps show the amount of rainfall in different areas. | D: rainfall. |
What is a germ cell that divides into gametocytes during gametogenesis?
Here are the choices:
A. gametogonium
B. gonads
C. pollenation
D. cocklebur | From gametogonium (plural, gametogonia ), male and female gametes develop differently - males by spermatogenesis and females by oogenesis. A gametogonium is a germ cell that divides into gametocytes during gametogenesis. Male gametogonia are called spermatogonia , and female gametogonia are called oogonia . However, the following pattern is common for both oogonia and soermatogonia (chromosome numbers depict human chromosomes):. | A: gametogonium. |
The saguaro doesn't have any leaves to lose water by which process?
Here are the choices:
A. propagation
B. evaporation
C. respiration
D. transpiration | The saguaro cactus pictured in Figure below has adapted in all three ways. When it was still a very small plant, just a few inches high, its shallow roots already reached out as much as 2 meters (7 feet) from the base of the stem. By now, its root system is much more widespread. It allows the cactus to gather as much moisture as possible from rare rainfalls. The saguaro doesn't have any leaves to lose water by transpiration. It also has a large, barrel-shaped stem that can store a lot of water. Thorns protect the stem from thirsty animals that might try to get at the water inside. | D: transpiration. |
What is the most important source of energy on earth?
Here are the choices:
A. sun
B. the earth's core
C. moon
D. water | The sunlight that reaches Earth is the planet’s most important source of energy. The energy in sunlight, called solar energy, is electromagnetic energy. This is a form of energy that travels through space in electric and magnetic waves. Solar energy can be used to heat homes and produce electricity in solar cells like those on the roof seen in the Figure below . Sunny areas receive plenty of sunlight to generate electricity, but solar energy may not be practical in areas that are often cloudy. | A: sun. |
What do cyclotrons use to cause particles to move in circular orbits?
Here are the choices:
A. occurs field
B. magnetic field
C. layers field
D. mixed field | Figure 33.8 Cyclotrons use a magnetic field to cause particles to move in circular orbits. As the particles pass between the plates of the Ds, the voltage across the gap is oscillated to accelerate them twice in each orbit. | B: magnetic field. |
An example of a variable relating to the ramp is its what?
Here are the choices:
A. mass
B. color
C. weight
D. steepness | A: Variables might include factors relating to the ramp or to the object. An example of a variable relating to the ramp is its steepness. An example of a variable relating to the object is the way it moves—it might roll or slide down the ramp. Either of these variables could be manipulated by the researcher, so you could choose one of them for your manipulated variable. | D: steepness. |
Deep within the earth what force is so great that a rock behaves like a stretched rubber band?
Here are the choices:
A. magnetism
B. momentum
C. pressure
D. volcanoes | The amount of stress on a rock may be greater than the rock’s strength. In that case, the rock will undergo strain or deformation ( Figure below ). Deep within the Earth, the pressure is very great. A rock behaves like a stretched rubber band. When the stress stops, the rock goes back to its original shape. If more stress is applied to the rock, it bends and flows. It does not return to its original shape. Near the surface, if the stress continues, the rock will fracture (rupture) and break. | C: pressure. |
What shape is the colony of a volvox cell?
Here are the choices:
A. coil-shaped
B. pyramid
C. hollow ball shaped
D. tubular | Volvox Colony. Volvox cells live in a colony shaped like a hollow ball. The cells of the colony may be connected by strands of cytoplasm and can function together. For example, the whole colony can swim from one place to another as one. | C: hollow ball shaped. |
What do puffer fish produce to protect itself?
Here are the choices:
A. venom
B. enzymes
C. hormones
D. teeth | This odd-looking creature is a fish called a puffer fish. Like all fish, puffer fish are vertebrates. The puffer fish puffs up by rapidly filling its stretchy stomach with water. The reason? Getting bigger makes the fish seem larger to potential predators. Just to be on the safe side, the puffer fish also produces venom. In fact, it’s the second-most-poisonous vertebrate in the world after the poison dart frog. In this chapter, you’ll learn more about vertebrates such as these. You’ll find out that vertebrates are a diverse and fascinating group of animals. | A: venom. |
What are polymers composed of many sugar building blocks called?
Here are the choices:
A. monomers
B. hydrocarbons
C. polysaccharides
D. monosaccarides | C: polysaccharides. | |
Most gas molecules in the atmosphere are pulled close to earth’s surface by what force?
Here are the choices:
A. gravity
B. traction
C. weight
D. light | Like water in the ocean, air in the atmosphere exerts pressure that increases with depth. Most gas molecules in the atmosphere are pulled close to Earth’s surface by gravity. As a result, air pressure decreases quickly at lower altitudes and then more slowly at higher altitudes. This is illustrated in Figure below . Air pressure is greatest at sea level, where the depth of the atmosphere is greatest. At higher altitudes, the pressure is less because the depth of the atmosphere is less. For example, on top of Mount Everest, the tallest mountain on Earth, air pressure is only about one-third of the pressure at sea level. At such high altitudes, low air pressure makes it hard to breathe and is dangerous to human health. | A: gravity. |
Coral reefs and tropical rainforests are ecosystems known for what, contributing greatly to the species in existence on earth?
Here are the choices:
A. spontaneous mutation
B. commensalism
C. mass migrations
D. biodiversity | How many species actually exist in the world? No one knows for sure because only a small percentage of them have already been discovered. Estimates range from 5 to 30 million total species currently in existence. Many of them live on coral reefs and in tropical rainforests (see Figure below ). These two ecosystems have some of the greatest biodiversity on the planet. | D: biodiversity. |
Gymnosperms and angiosperms are types of _________ seed plants.
Here are the choices:
A. heritage
B. extinct
C. modern
D. genetic | Modern seed plants include gymnosperms and angiosperms. | C: modern. |
Not getting enough calcium may cause what health problem?
Here are the choices:
A. diabetes
B. arthritis
C. osteoporosis
D. blindness | Not getting enough minerals can cause health problems. For example, not getting enough calcium may cause osteoporosis. This is a disease in which the bones become porous so they break easily. Getting too much of some minerals can also cause health problems. Many people get too much sodium. Sodium is added to most packaged foods. People often add more sodium to their food by using table salt. Too much sodium has been linked to high blood pressure in some people. | C: osteoporosis. |
What is the sequence of elementary steps that together comprise an entire chemical reaction called?
Here are the choices:
A. reaction circle
B. mechanical mechanism
C. reaction mechanism
D. basic reaction | The overall balanced equation for a chemical reaction does not always tell us how a reaction actually proceeds. In many cases, the overall reaction takes place in a series of small steps. An elementary step (or elementary reaction) is one step in a series of simple reactions that show the progress of a reaction at the molecular level. In terms of collision theory, each elementary step corresponds to a single collision. A reaction mechanism is the sequence of elementary steps that together comprise an entire chemical reaction. As an analogy, consider the route that you might take while driving to the grocery store. That route may consist of several turns, similar to the elementary steps. The overall reaction specifies only the beginning point (your house) and the final destination (the store), with no information about the specifics in between. | C: reaction mechanism. |
What is the clear, curved structure that works with the cornea to help focus light at the back of the eye?
Here are the choices:
A. iris
B. lens
C. pupil
D. retina | After passing into the eye through the pupil, light passes through the lens. The lens of the eye is a clear, curved structure. Along with the cornea, the lens helps focus light at the back of the eye. This is pictured below ( Figure below ). | B: lens. |
What is the color of the powder of a mineral called?
Here are the choices:
A. streak
B. dye
C. hue
D. pigment | Streak is the color of the powder of a mineral. To do a streak test, you scrape the mineral across an unglazed porcelain plate. The plate is harder than many minerals, causing the minerals to leave a streak of powder on the plate. The color of the streak often differs from the color of the larger mineral sample ( Figure below ). Yellow-gold pyrite has a blackish streak. This blackish streak tells you that the mineral is not gold, because gold has a gold-colored streak. | A: streak. |
What part of the plant anchors it into the soil?
Here are the choices:
A. buds
B. roots
C. leaves
D. stems | B: roots. | |
Evolution happens because of what?
Here are the choices:
A. natural selection
B. natural process
C. natural resources
D. natural change | Evolution happens because of natural selection . Good traits become more common in a population. Bad traits become less common. The deer mouse, species Peromyscus maniculatus gives an example of evolution by natural selection. In Nebraska, this mouse is typically brown. But in places where glaciers dropped lighter sand over the darker soil, the mice are light. Why? Because predators could more easily spot the dark mice on light sand. The lighter mice were more likely to survive and have offspring. Natural selection favored the light mice. Over time, the population became light colored. Enough changes may take place over time that the two types of mice become different species. | A: natural selection. |
The nephron is the functional unit of what pair of organs?
Here are the choices:
A. eyes
B. lungs
C. ribs
D. kidneys | Figure 41.6 The nephron is the functional unit of the kidney. The glomerulus and convoluted tubules are located in the kidney cortex, while collecting ducts are located in the pyramids of the medulla. (credit: modification of work by NIDDK). | D: kidneys. |
Nonshivering thermogenesis, which involves the breakdown of brown adipose tissue, is a special methods newborns have for what purpose?
Here are the choices:
A. losing heat
B. harnessing heat
C. generating heat
D. moving heat | Thermoregulatory Adjustments The fetus floats in warm amniotic fluid that is maintained at a temperature of approximately 98.6°F with very little fluctuation. Birth exposes newborns to a cooler environment in which they have to regulate their own body temperature. Newborns have a higher ratio of surface area to volume than adults. This means that their body has less volume throughout which to produce heat, and more surface area from which to lose heat. As a result, newborns produce heat more slowly and lose it more quickly. Newborns also have immature musculature that limits their ability to generate heat by shivering. Moreover, their nervous systems are underdeveloped, so they cannot quickly constrict superficial blood vessels in response to cold. They also have little subcutaneous fat for insulation. All these factors make it harder for newborns to maintain their body temperature. Newborns, however, do have a special method for generating heat: nonshivering thermogenesis, which involves the breakdown of brown adipose tissue, or brown fat, which is distributed over the back, chest, and shoulders. Brown fat differs from the more familiar white fat in two ways: • It is highly vascularized. This allows for faster delivery of oxygen, which leads to faster cellular respiration. • It is packed with a special type of mitochondria that are able to engage in cellular respiration reactions that produce less ATP and more heat than standard cellular respiration reactions. | C: generating heat. |
What do you call a predator species that affects other species' populations when its own population size changes?
Here are the choices:
A. keystone species
B. symbiotic species
C. complement species
D. paradox species | Some predator species play a special role in their community. They are called keystone species. When the population size of a keystone species changes, the populations of many other species are affected. Prairie dogs, pictured in Figure below , are an example of a keystone species. Their numbers affect most of the other species in their community. Prairie dog actions improve the quality of soil and water for plants, upon which most other species in the community depend. | A: keystone species. |
What do you call the electrons in the outer energy level of an atom that are involved in chemical bonds?
Here are the choices:
A. transitions electrons
B. helium electrons
C. valence electrons
D. force electrons | Carbon is a nonmetal in group 14 of the periodic table. Like other group 14 elements, carbon has four valence electrons. Valence electrons are the electrons in the outer energy level of an atom that are involved in chemical bonds. The valence electrons of carbon are shown in the electron dot diagram in the Figure below . | C: valence electrons. |
How many valence electrons do neutral phosphorus atoms have?
Here are the choices:
A. nine
B. five
C. three
D. four | The highest-numbered shell is the third shell, which has 2 electrons in the 3s subshell and 3 electrons in the 3p subshell. That gives a total of 5 electrons, so neutral phosphorus atoms have 5 valence electrons. The 10 remaining electrons, from the first and second shells, are core electrons. | B: five. |
What impact does photosynthesis have on the direction of electron flow?
Here are the choices:
A. cycles it
B. cools it
C. reverses it
D. repeats it | C: reverses it. | |
In an experiment, what is kept constant so they will not affect the results, including affecting the dependent variable?
Here are the choices:
A. similar controls
B. educated controls
C. experimental controls
D. atmospheric controls | Experimental controls are other factors that might affect the dependent variable. They are kept constant so they will not affect the results of the experiment. | C: experimental controls. |
The rate of evaporation depends only on the surface area of the liquid and is essentially constant. the rate of condensation depends on the number of molecules in the vapor phase and increases steadily until it equals the rate of this?
Here are the choices:
A. accumulation
B. absorption
C. condensation
D. evaporation | The rate of evaporation depends only on the surface area of the liquid and is essentially constant. The rate of condensation depends on the number of molecules in the vapor phase and increases steadily until it equals the rate of evaporation. | D: evaporation. |
What are the two main types of diabetes?
Here are the choices:
A. type 0, 1
B. type 3, 4
C. type a, b
D. type 1, type 2 | There are two main types of diabetes: type 1 diabetes and type 2 diabetes. The two types of diabetes have different causes. | D: type 1, type 2. |
What function does the longer flagellae perform in dinoflagellates?
Here are the choices:
A. defends
B. attacks
C. propels
D. grasps | 22.11.5 Pyrrophytes Pyrrophytes are unicellular, photosynthetic, and mostly aquatic. They have protective coats composed of stiff cellulose. They are more easily identifiable, due to the presence of two flagellae. The longer flagellae propels the dinoflagellate, while the second shorter, flatter flagellae functions as a rudder. Some species of pyrrophytes are zooxanthellae. Since they lack cellulose plates, they make their home in coral reefs and animals, such as sea anemones, and molluscs. In returning the favour of sheltering them, dinoflagellates provide carbohydrates to their host through photosynthesis. This is why there are nutrient-rich coral reefs in malnutritions water. A negative aspect of pyrrophytes is that under certain conditions, species of dinoflagellates reproduce rapidly to form a harmful algal bloom (HAB), known as a red tide if dinoflagellates are the cause. Such pyrrophytes can produce toxins which may injure or kill wildlife, and additionally any consumers of contaminated wildlife. | C: propels. |
What are the three stages of water?
Here are the choices:
A. liquid, underground, frozen
B. ice, liquid, vapor
C. vapor, earth, internal
D. ice, rock, sky | (A) Natalie Lucier; (B) Gareth Haywood; (C) Lynn Greyling. Ice, liquid, and water vapor are the three phases of water . (A) CC BY 2.0; (B) CC BY 2.0; (C) Public Domain. | B: ice, liquid, vapor. |
What is the first stage of cellular respiration?
Here are the choices:
A. defacation
B. photosynthesis
C. breath
D. glycolysis | Glycolysis is the first stage of cellular respiration. It takes place in the cytoplasm of the cell. The world glycolysis means "glucose splitting". That's exactly what happens in this stage. Enzymes split a molecule of glucose into two smaller molecules called pyruvate. This results in a net gain of two molecules of ATP. Other energy-storing molecules are also produced. (Their energy will be used in stage 3 to make more ATP. ) Glycolysis does not require oxygen. Anything that doesn't need oxygen is described as anaerobic . | D: glycolysis. |
Roundworms are intervertebrates that belong to which phylum?
Here are the choices:
A. amoebozoa
B. Gordiacea
C. nematoda
D. annelida | Roundworms are invertebrates in Phylum Nematoda. Roundworms have a pseudocoelom and complete digestive system. They are free-living heterotrophs or parasites. | C: nematoda. |
The development of multi-cellular organisms begins from a single-celled zygote, which undergoes rapid cell division to form this?
Here are the choices:
A. eukaryote
B. multicell
C. gametophyte
D. blastula | Cleavage and Blastula Stage The development of multi-cellular organisms begins from a single-celled zygote, which undergoes rapid cell division to form the blastula. The rapid, multiple rounds of cell division are termed cleavage. Cleavage is illustrated in (Figure 43.24a). After the cleavage has produced over 100 cells, the embryo is called a blastula. The blastula is usually a spherical layer of cells (the blastoderm) surrounding a fluid-filled or yolk-filled cavity (the blastocoel). Mammals at this stage form a structure called the blastocyst, characterized by an inner cell mass that is distinct from the surrounding blastula, shown in Figure 43.24b. During cleavage, the cells divide without an increase in mass; that is, one large single-celled zygote divides into multiple smaller cells. Each cell within the blastula is called a blastomere. | D: blastula. |
While components of a mixture can be separated by physical means, the components of a pure substance can only be broken down through what means?
Here are the choices:
A. mechanical
B. thermal
C. radiation
D. chemical | In the previous lesson, we discussed pure substances and mixtures. We indicated that the components of a mixture could be separated by physical means, but the components of a pure substance could not. Pure substances can only be broken down further through chemical means. In this lesson, we list several methods for separating mixtures. We will also be looking at chemical changes which alter the chemical identity of a substance, and how to recognize when a chemical change is taking place. | D: chemical. |
What is it called when pollen from one plant fertilizes another plant of the same species?
Here are the choices:
A. cross-pollination
B. cross - vegetation
C. cross-breeding
D. cross-typing | Pea plants are naturally self-pollinating. In self-pollination , pollen grains from anthers on one plant are transferred to stigmas of flowers on the same plant. Mendel was interested in the offspring of two different parent plants, so he had to prevent self-pollination. He removed the anthers from the flowers of some of the plants in his experiments. Then he pollinated them by hand with pollen from other parent plants of his choice. When pollen from one plant fertilizes another plant of the same species, it is called cross-pollination . The offspring that result from such a cross are called hybrids. | A: cross-pollination. |
Calcium hydroxide and calcium carbonate are effective in neutralizing the effects of what on lakes?
Here are the choices:
A. dioxide rain
B. ozone rain
C. acid rain
D. oil rain | Calcium hydroxide and calcium carbonate are effective in neutralizing the effects of acid rain on lakes. Suggest other compounds that might be effective in treating lakes. Give a plausible reason to explain why Ca(OH)2 and CaCO3 are used. ♦ Approximately 95% of the chlorine produced industrially comes from the electrolysis of sodium chloride solutions (brine): NaCl(aq) + H2O(l) → Cl2(g) + H2(g) + NaOH(aq) Chlorine is a respiratory irritant whose presence is easily detected by its penetrating odor and greenishyellow color. One use for the chlorine produced is in the manufacture of hydrochloric acid. | C: acid rain. |
Most of these bacterial illnesses can be prevented with proper cooking of food and washing what?
Here are the choices:
A. hair
B. teeth
C. hands
D. vegetables | Bacteria that cause foodborne illnesses include Salmonella , a bacterium found in many foods, including raw and undercooked meat, poultry, dairy products, and seafood. Campylobacter jejuni is found in raw or undercooked chicken and unpasteurized milk. Several strains of E. coli can cause illnesses, and are found in raw or undercooked hamburger, unpasteurized fruit juices and milk, and even fresh produce. Vibrio is a bacterium that may contaminate fish or shellfish. Listeria has been found in raw and undercooked meats, unpasteurized milk, soft cheeses, and ready-to-eat deli meats and hot dogs. Most of these bacterial illnesses can be prevented with proper cooking of food and washing of hands. | C: hands. |
If something is in the state of matter where it has both a definite shape and volume, then what state of matter is it in?
Here are the choices:
A. plasma
B. gas
C. liquid
D. solid | D: solid. | |
What is the region known as the myelencephalon in the embryonic brain?
Here are the choices:
A. Mesencephalon
B. Telencephalon
C. medulla
D. Diencephalon | Medulla The medulla is the region known as the myelencephalon in the embryonic brain. The initial portion of the name, “myel,” refers to the significant white matter found in this region—especially on its exterior, which is continuous with the white. | C: medulla. |
What involves the reaction of a hydrocarbon with oxygen gas to produce water and carbon dioxide?
Here are the choices:
A. material reactions
B. hydrogen reactions
C. chemical reactions
D. combustion reactions | Combustion reactions involve the reaction of a hydrocarbon with oxygen gas to produce water and carbon dioxide. | D: combustion reactions. |
What law states that matter cannot be created or destroyed?
Here are the choices:
A. construct of energy
B. Murphy's Law
C. law of inertia
D. conservation of energy | The law of conservation of energy states that matter cannot be created or destroyed. Whether a chemical reaction absorbs or releases energy, there is no overall change in the amount of energy during the reaction. | D: conservation of energy. |
The air bubbles resulting from cavitation expand and block water channels of the what?
Here are the choices:
A. respiration
B. heart
C. ectoderm
D. xylem | D: xylem. | |
Which gender typically experiences growth spurts first?
Here are the choices:
A. no difference
B. male
C. transgender
D. female | Like boys, girls also go through an adolescent growth spurt . However, girls typically start their growth spurt a year or two earlier than boys (and therefore a couple of centimeters shorter, on average). Girls also have a shorter growth spurt. For example, they typically reach their adult height by about age 15. In addition, girls generally do not grow as fast as boys do during the growth spurt, even at their peak rate of growth. As a result, females are about 10 centimeters (about 4 inches) shorter, on average, than males by the time they reach their final height. | D: female. |
What are the only organisms that can decompose wood?
Here are the choices:
A. fossil
B. bacteria
C. fungi
D. protists | Saprotrophs are the final step in decomposition. They feed on any remaining organic matter that is left after other decomposers do their work. Saprotrophs include fungi and single-celled protozoa. Fungi are the only organisms that can decompose wood. | C: fungi. |
What part of the plant do nutrients enter?
Here are the choices:
A. the roots
B. the stem
C. the seeds
D. the flower | A: the roots. | |
What is a solid particle that is indestructible?
Here are the choices:
A. quark
B. nucleus
C. atom
D. neutron | Atoms are solid particles that are indestructible. | C: atom. |
Activated macrophages and neutrophils discharge what that signals molecules that enhance an immune response?
Here are the choices:
A. nucelotides
B. pathogens
C. alkaloids
D. cytokines | D: cytokines. | |
The extracellular fluid is in contact with the axon membrane only at what location?
Here are the choices:
A. dendrites
B. synapses
C. the nodes
D. Sensory Receptors | C: the nodes. | |
Muscarinic receptors can cause both depolarization or hyperpolarization depending on the what?
Here are the choices:
A. strain
B. subtype
C. gravity
D. phenotype | Nicotinic receptor causes depolarization. Muscarinic receptors can cause both depolarization or hyperpolarization depending on the subtype. | B: subtype. |
What does rising air do when it reaches the top of the troposphere?
Here are the choices:
A. warms
B. cools
C. dries
D. heats | The rising air cools as it reaches the top of the troposphere. The air gets denser, so it sinks to the surface. The sinking, heavy air creates an area of high air pressure near the ground. | B: cools. |
The what is the number of wave cycles that pass a specified point in space in a specified amount of time?
Here are the choices:
A. density
B. vibrancy
C. intensity
D. frequency | Waves need not be restricted to travel through matter. As Maxwell showed, electromagnetic waves consist of an electric field oscillating in step with a perpendicular magnetic field, both of which are perpendicular to the direction of travel. These waves can travel through a vacuum at a constant speed of 2.998 × 108 m/s, the speed of light (denoted by c). All waves, including forms of electromagnetic radiation, are characterized by, a wavelength (denoted by λ, the lowercase Greek letter lambda), a frequency (denoted by ν, the lowercase Greek letter nu), and an amplitude. As can be seen in Figure 6.2, the wavelength is the distance between two consecutive peaks or troughs in a wave (measured in meters in the SI system). Electromagnetic waves have wavelengths that fall within an enormous range-wavelengths of kilometers (103 m) to picometers (10−12 m) have been observed. The frequency is the number of wave cycles that pass a specified point in space in a specified amount of time (in the SI system, this is measured in seconds). A cycle corresponds to one complete wavelength. The unit for frequency, expressed as cycles per second [s−1], is the hertz (Hz). Common multiples of this unit are megahertz, (1 MHz = 1 × 106 Hz) and gigahertz (1 GHz = 1 × 109 Hz). The amplitude corresponds to the magnitude of the wave's displacement and so, in Figure 6.2, this corresponds to one-half the height between the peaks and troughs. The amplitude is related to the intensity of the wave, which for light is the brightness, and for sound is the loudness. | D: frequency. |
Intermediate filaments tend to give the structural stability to what?
Here are the choices:
A. muscles
B. cells
C. proteins
D. nerves | 8.7.1 Intermediate Filaments These are rope like filaments, 8-10nm in diameter and tend to give the structural stability to cells. Examples inculude Vimentin, neurofilaments and keratin. It is keratin which priniciply makes up hair, nails and horns. | B: cells. |
What is the process in which a layer of a second metal is deposited on the metal electrode that acts as the cathode during electrolysis?
Here are the choices:
A. distillation
B. cold fusion
C. casting
D. electroplating | Electroplating In a process called electroplating, a layer of a second metal is deposited on the metal electrode that acts as the cathode during electrolysis. Electroplating is used to enhance the appearance of metal objects and protect them from corrosion. Examples of electroplating include the chromium layer found on many bathroom fixtures or (in earlier days) on the bumpers and hubcaps of cars, as well as the thin layer of precious metal that coats silver-plated dinnerware or jewelry. In all cases, the basic concept is the same. A schematic view of an apparatus for electroplating silverware and a photograph of a commercial electroplating cell are shown in Figure 19.24 "Electroplating". | D: electroplating. |
What is the term for diseases in which blood does not clot normally?
Here are the choices:
A. hemophilia
B. arthritis
C. lymphoma
D. diabetes | Hemophilia is a group of diseases in which blood does not clot normally. Factors in blood are involved in clotting. When you bleed, your body begins a coagulation cascade of reactions, involving special proteins known as coagulation factors, to stop that bleeding. When one or more of these clotting factors are missing, there is a higher chance of having dificulties stoping the bleeding. Hemophiliacs lacking the normal Factor VIII are said to have Hemophilia A (or Factor VIII deficiency), the most common form. Hemophilia is a genetic disease, passed down through family. It is linked to the X-chromosome, so it mostly affects males. F8 is the gene for the Factor VIII protein. Mutations in the F8 gene lead to the production of an abnormal version of coagulation factor VIII, or reduce the amount of the protein. The altered or missing protein cannot participate effectively in the blood clotting process. | A: hemophilia. |
Cardiomyocytes are striated muscle cells found where?
Here are the choices:
A. in the diaphram
B. in lung tissue
C. in the intestines
D. in cardiac tissue | Figure 40.13 Cardiomyocytes are striated muscle cells found in cardiac tissue. (credit: modification of work by Dr. Girod, Anton Becker; scale-bar data from Matt Russell). | D: in cardiac tissue. |
Which protein, that stores oxygen in muscle cells, has been purified from a number of organisms?
Here are the choices:
A. melanin
B. potassium
C. myoglobin
D. iodine | Myoglobin, a protein that stores oxygen in muscle cells, has been purified from a number of organisms. The protein from a sperm whale is composed of 153 amino acid units. What is the minimum number of nucleotides that must be present in the mRNA that codes for this protein?. | C: myoglobin. |
A membrane has what property if it can control what molecules or ions enter or leave the cell?
Here are the choices:
A. impermeability
B. indiscreet permeability
C. susceptible permeability
D. selective permeability | Probably the most important feature of a cell’s phospholipid membranes is that they are selectively permeable or semipermeable . A membrane that is selectively permeable has control over what molecules or ions can enter or leave the cell, as shown in Figure below . The permeability of a membrane is dependent on the organization and characteristics of the membrane lipids and proteins. In this way, cell membranes help maintain a state of homeostasis within cells (and tissues, organs, and organ systems) so that an organism can stay alive and healthy. | D: selective permeability. |
What is the term for the amount of space taken up by an object?
Here are the choices:
A. size
B. weight
C. volume
D. mass | C: volume. | |
What is the most common form of cancer in women?
Here are the choices:
A. breast cancer
B. ovarian cancer
C. melanoma
D. lung cancer | The most common type of cancer in females is breast cancer . The cancer causes the cells of the breast to grow out of control and form a tumor. Breast cancer is rare in teens. It becomes more common as women get older. If breast cancer is found early, it usually can be cured with surgery. | A: breast cancer. |
Exposure to what is the most common cause of hearing loss?
Here are the choices:
A. Guitar
B. angry sounds
C. outside sounds
D. loud sounds | The most common cause of hearing loss is exposure to loud sounds. Loud sounds damage hair cells in the ear that are needed for hearing. Louder sounds damage hair cells more quickly than softer sounds. | D: loud sounds. |
What basic plant structures generally have large surface areas and high surface-to-volume ratios?
Here are the choices:
A. flowers
B. leaves
C. roots
D. stems | B: leaves. | |
What is the main component of phytoplankton?
Here are the choices:
A. cells
B. amoebas
C. algae
D. seawater | Algae play significant roles as producers in aquatic ecosystems. Microscopic forms live suspended in the water column. They are the main component of phytoplankton. As such, they contribute to the food base of most marine ecosystems. | C: algae. |
Metabolic enzymes catalyze catabolic reactions that break down what?
Here are the choices:
A. proteins
B. carbohydrates
C. lipids
D. impurities | 24.2 Carbohydrate Metabolism Metabolic enzymes catalyze catabolic reactions that break down carbohydrates contained in food. The energy released is used to power the cells and systems that make up your body. Excess or unutilized energy is stored as fat or glycogen for later use. Carbohydrate metabolism begins in the mouth, where the enzyme salivary amylase begins to break down complex sugars into monosaccharides. These can then be transported across the intestinal membrane into the bloodstream and then to body tissues. In the cells, glucose, a six-carbon sugar, is processed through a sequence of reactions into smaller sugars, and the energy stored inside the molecule is released. The first step of carbohydrate catabolism is glycolysis, which produces pyruvate, NADH, and ATP. Under anaerobic conditions, the pyruvate can be converted into lactate to keep glycolysis working. Under aerobic conditions, pyruvate enters the Krebs cycle, also called the citric acid cycle or tricarboxylic acid cycle. In addition to ATP, the Krebs cycle produces high-energy FADH2 and NADH molecules, which provide electrons to the oxidative phosphorylation process that generates more high-energy ATP molecules. For each molecule of glucose that is processed in glycolysis, a net of 36 ATPs can be created by aerobic respiration. Under anaerobic conditions, ATP production is limited to those generated by glycolysis. While a total of four ATPs are produced by glycolysis, two are needed to begin glycolysis, so there is a net yield of two ATP molecules. In conditions of low glucose, such as fasting, starvation, or low carbohydrate diets, glucose can be synthesized from lactate, pyruvate, glycerol, alanine, or glutamate. This process, called gluconeogenesis, is almost the reverse of glycolysis and serves to create glucose molecules for glucose-dependent organs, such as the brain, when glucose levels fall below normal. | B: carbohydrates. |
Ponds and lakes are examples of what kind of biome?
Here are the choices:
A. standing liquid biome
B. standing marine biome
C. standing freshwater biome
D. standing lake biome | Freshwater biomes have water that contains little or no salt. They include standing and running freshwater biomes. Standing freshwater biomes include ponds and lakes. Lakes are generally bigger and deeper than ponds. Some of the water in lakes is in the aphotic zone, where there is too little sunlight for photosynthesis. Plankton and plants, such as the duckweed in Figure below , are the primary producers in standing freshwater biomes. | C: standing freshwater biome. |
The skeletons of humans and horses are examples of what?
Here are the choices:
A. endoskeletons
B. hydroskeleton
C. pliant skeletons
D. exoskeletons | Figure 38.4 The skeletons of humans and horses are examples of endoskeletons. (credit: Ross Murphy). | A: endoskeletons. |
What type of tissue transports water, nutrients, and food in plants?
Here are the choices:
A. normal tissue
B. vascular tissue
C. rough tissue
D. smooth tissue | A later adaption for life on land was the evolution of vascular tissue. Vascular tissue is specialized tissue that transports water, nutrients, and food in plants. In algae, vascular tissue is not necessary since the entire body is in contact with the water, and the water simply enters the algae. But on land, water may only be found deep in the ground. Vascular tissues take water and nutrients from the ground up into the plant, while also taking food down from the leaves into the rest of the plant. The two vascular tissues are xylem and phloem. Xylem is responsible for the transport of water and nutrients from the roots to the rest of the plant. Phloem carries the sugars made in the leaves to the parts of the plant where they are needed. | B: vascular tissue. |
Stomata are special pores that allow gasses to enter and exit what?
Here are the choices:
A. the skin
B. the leaf
C. the flower
D. the soil | Stomata are special pores that allow gasses to enter and exit the leaf. | B: the leaf. |
What is created when the wave source moves faster than the wave propagation speed?
Here are the choices:
A. bow wake
B. superceding wake
C. piece wake
D. loop wake | Sonic booms are one example of a broader phenomenon called bow wakes. A bow wake, such as the one in Figure 17.19, is created when the wave source moves faster than the wave propagation speed. Water waves spread out in circles from the point where created, and the bow wake is the familiar V-shaped wake trailing the source. A more exotic bow wake is created when a subatomic particle travels through a medium faster than the speed of light travels in that medium. (In a vacuum, the maximum 8 speed of light will be c = 3.00×10 m/s ; in the medium of water, the speed of light is closer to 0.75c . If the particle creates light in its passage, that light spreads on a cone with an angle indicative of the speed of the particle, as illustrated in Figure 17.20. Such a bow wake is called Cerenkov radiation and is commonly observed in particle physics. | A: bow wake. |
In a transverse wave, the highest point the wave reaches is known as the?
Here are the choices:
A. flow
B. crest
C. axis
D. valley | In a transverse wave, particles of the medium move up and down at right angles to the direction of the wave. Wave amplitude of a transverse wave is the difference in height between the crest and the resting position. The crest is the highest point particles of the medium reach. The higher the crests are, the greater the amplitude of the wave. | B: crest. |
Which orbitals do electrons fill first?
Here are the choices:
A. furthest from nucleus
B. charged orbitals
C. empty orbitals
D. closest to the nucleus | Electrons fill orbitals in a consistent order: they first fill the orbitals closest to the nucleus, then they continue to fill orbitals of increasing energy further from the nucleus. If there are multiple orbitals of equal energy, they will be filled with one electron in each energy level before a second electron is added. The electrons of the outermost energy level determine the energetic stability of the atom and its tendency to form chemical bonds with other atoms to form molecules. Under standard conditions, atoms fill the inner shells first, often resulting in a variable number of electrons in the outermost shell. The innermost shell has a maximum of two electrons but the next two electron shells can each have a maximum of eight electrons. This is known as the octet rule, which states, with the exception of the innermost shell, that atoms are more stable energetically when they have eight electrons in their valence shell, the outermost electron shell. Examples of some neutral atoms and their electron configurations are shown in Figure 2.7. Notice that in this Figure 2.7, helium has a complete outer electron shell, with two electrons filling its first and only shell. Similarly, neon has a complete outer 2n shell containing eight electrons. In contrast, chlorine and sodium have seven and one in their outer shells, respectively, but theoretically they would be more energetically stable if they followed the octet rule and had eight. | D: closest to the nucleus. |
Many discrete characters are determined by a single gene locus with different alleles that produce distinct what?
Here are the choices:
A. phototypes
B. clusters
C. phenotypes
D. subtypes | C: phenotypes. | |
What is the hardest type of coal?
Here are the choices:
A. anthracite
B. peat
C. lignite
D. Bituminous | 5. Anthracite is the hardest type of coal because it is metamorphic. Anthracite causes less pollution when it burns. Why do you think that is?. | A: anthracite. |
All cells have voltages across their what?
Here are the choices:
A. plasma membranes
B. ribosomes
C. nuclei
D. display membranes | A: plasma membranes. | |
Which is the largest planet in our solar system?
Here are the choices:
A. jupiter
B. neptune
C. uranus
D. titan | Jupiter is the largest planet in our solar system. | A: jupiter. |
A crucial function of the cranial nerves is to keep visual stimuli centered on the fovea of what eye structure?
Here are the choices:
A. pupil
B. retina
C. scelra
D. iris | Testing eye movement is simply a matter of having the patient track the tip of a pen as it is passed through the visual field. This may appear similar to testing visual field deficits related to the optic nerve, but the difference is that the patient is asked to not move the eyes while the examiner moves a stimulus into the peripheral visual field. Here, the extent of movement is the point of the test. The examiner is watching for conjugate movements representing proper function of the related nuclei and the MLF. Failure of one eye to abduct while the other adducts in a horizontal movement is referred to as internuclear ophthalmoplegia. When this occurs, the patient will experience diplopia, or double vision, as the two eyes are temporarily pointed at different stimuli. Diplopia is not restricted to failure of the lateral rectus, because any of the extraocular muscles may fail to move one eye in perfect conjugation with the other. The final aspect of testing eye movements is to move the tip of the pen in toward the patient’s face. As visual stimuli move closer to the face, the two medial recti muscles cause the eyes to move in the one nonconjugate movement that is part of gaze control. When the two eyes move to look at something closer to the face, they both adduct, which is referred to as convergence. To keep the stimulus in focus, the eye also needs to change the shape of the lens, which is controlled through the parasympathetic fibers of the oculomotor nerve. The change in focal power of the eye is referred to as accommodation. Accommodation ability changes with age; focusing on nearer objects, such as the written text of a book or on a computer screen, may require corrective lenses later in life. Coordination of the skeletal muscles for convergence and coordination of the smooth muscles of the ciliary body for accommodation are referred to as the accommodation–convergence reflex. A crucial function of the cranial nerves is to keep visual stimuli centered on the fovea of the retina. The vestibulo-ocular reflex (VOR) coordinates all of the components (Figure 16.10), both sensory and motor, that make this possible. If the head rotates in one direction—for example, to the right—the horizontal pair of semicircular canals in the inner ear indicate the movement by increased activity on the right and decreased activity on the left. The information is sent to the abducens nuclei and oculomotor nuclei on either side to coordinate the lateral and medial rectus muscles. The left lateral rectus and right medial rectus muscles will contract, rotating the eyes in the opposite direction of the head, while nuclei controlling the right lateral rectus and left medial rectus muscles will be inhibited to reduce antagonism of the contracting muscles. | B: retina. |
In what process is energy from the sun converted to stored chemical energy in an organism?
Here are the choices:
A. cellular respiration
B. metabolism
C. photosynthesis
D. digestion | There is no reason to think that the alignment of the stars has anything to do with events that happen on Earth. The constellations are patterns made from stars in the sky. The patterns do not reflect any characteristics of the stars themselves. When scientific tests are done to provide evidence in support of astrological ideas, the tests fail. When a scientific idea fails, it is abandoned or modified. Astrologers do not change or abandon their ideas when they fail. So astrology is not science. | C: photosynthesis. |
Sunlight gives plants the energy they need for what?
Here are the choices:
A. glycolysis
B. absorption
C. photosynthesis
D. respiration | Plants can get the energy they need for photosynthesis from either sunlight or artificial light. | C: photosynthesis. |
What is lowered when salts go into ion form?
Here are the choices:
A. resistance
B. charge
C. power
D. voltage | Most of the body’s resistance is in its dry skin. When wet, salts go into ion form, lowering the resistance significantly. The interior of the body has a much lower resistance than dry skin because of all the ionic solutions and fluids it contains. If skin resistance is bypassed, such as by an intravenous infusion, a catheter, or exposed pacemaker leads, a person is rendered microshock sensitive. In this condition, currents about 1/1000 those listed in Table 20.3 produce similar effects. During open-heart surgery, currents as small as 20 μA can be used to still the heart. Stringent electrical safety requirements in hospitals, particularly in surgery and intensive care, are related to the doubly disadvantaged microshock-sensitive patient. The break in the skin has reduced his resistance, and so the same voltage causes a greater current, and a much smaller current has a greater effect. | A: resistance. |
What is produced during the hydrogenation of vegetable oils?
Here are the choices:
A. rich fatty acids
B. partially-hydrogenated fatty acids
C. trans fatty acids
D. complete fatty acids | taste, and nutrition of butter. (Preservatives and antioxidants are also added. ) In most commercial peanut butter, the peanut oil has been partially hydrogenated to prevent it from separating out. Consumers could decrease the amount of saturated fat in their diet by using the original unprocessed oils on their foods, but most people would rather spread margarine on their toast than pour oil on it. Many people have switched from butter to margarine or vegetable shortening because of concerns that saturated animal fats can raise blood cholesterol levels and result in clogged arteries. However, during the hydrogenation of vegetable oils, an isomerization reaction occurs that produces the trans fatty acids mentioned in the opening essay. However, studies have shown that trans fatty acids also raise cholesterol levels and increase the incidence of heart disease. Trans fatty acids do not have the bend in their structures, which occurs in cis fatty acids and thus pack closely together in the same way that the saturated fatty acids do. Consumers are now being advised to use polyunsaturated oils and soft or liquid margarine and reduce their total fat consumption to less than 30% of their total calorie intake each day. Fats and oils that are in contact with moist air at room temperature eventually undergo oxidation and hydrolysis reactions that cause them to turn rancid, acquiring a characteristic disagreeable odor. One cause of the odor is the release of volatile fatty acids by hydrolysis of the ester bonds. Butter, for example, releases foul-smelling butyric, caprylic, and capric acids. Microorganisms present in the air furnish lipases that catalyze this process. Hydrolytic rancidity can easily be prevented by covering the fat or oil and keeping it in a refrigerator. Another cause of volatile, odorous compounds is the oxidation of the unsaturated fatty acid components, particularly the readily oxidized structural unit. | C: trans fatty acids. |
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