questions stringlengths 37 1.22k | reasoning stringlengths 0 3.56k ⌀ | answers stringlengths 4 138 |
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What structures include the vagina, uterus, ovaries, and fallopian tubes?
Here are the choices:
A. skeletal
B. digestion
C. reproductive
D. respiration | Female reproductive structures include the vagina, uterus, ovaries, and fallopian tubes. | C: reproductive. |
Where do the steps in the water cycle begin?
Here are the choices:
A. sky
B. the ocean
C. rivers
D. clouds | The water cycle does not have a real starting or ending point. It is an endless recycling process that involves the oceans, lakes and other bodies of water, as well as the land surfaces and the atmosphere. The steps in the water cycle are as follows, starting with the water in the oceans:. | B: the ocean. |
What does the structure of a protein start with?
Here are the choices:
A. amino acids
B. dna acids
C. rna acids
D. organism acids | Protein Structure. The structure of a protein starts with its sequence of amino acids. What determines the secondary structure of a protein? What are two types of secondary protein structure?. | A: amino acids. |
What is the small intestine lined with that helps with nutrient absorption?
Here are the choices:
A. hilum
B. villi
C. bile
D. cannula | Image copyright Sebastian Kaulitzki, 2013. The small intestine is lined with tiny villi that help absorb nutrients . Used under license from Shutterstock. com. | B: villi. |
What visual property of soil indicates fertility and nitrogen content?
Here are the choices:
A. color
B. quality
C. texture
D. contrast | The color of soil indicates its fertility. Black or dark brown soils are rich in nitrogen and contain a high percentage of organic materials. Soils that are nitrogen poor and low in organic material might be gray, yellow, or red. | A: color. |
What waves require a material medium such as water, air, or rope?
Here are the choices:
A. potential
B. electromagnetic
C. mechanical
D. light | Water waves, sound waves, and the waves that travel along a rope are mechanical waves . Mechanical waves require a material medium such as water, air, or rope. Light waves, however, are electromagnetic waves and travel without a material medium. They are not mechanical waves. | C: mechanical. |
Which continent is covered with an ice cap?
Here are the choices:
A. antarctica
B. asia
C. greenland
D. australia | The continent of Antarctica is covered with an ice cap. | A: antarctica. |
What type of organisms do carnivores feed on?
Here are the choices:
A. plants
B. decomposers
C. eggs
D. animals | Carnivores feed on animals, either herbivores or other carnivores. Snakes that eat mice are carnivores. Hawks that eat snakes are also carnivores ( Figure below ). | D: animals. |
What is the ability to be attracted by a magnet and to act as a magnet?
Here are the choices:
A. polarization
B. inertia
C. electrical attraction
D. magnetism | Magnetism is the ability to be attracted by a magnet and to act as a magnet. Only ferromagnetic materials have this property. They include iron, cobalt, and nickel. When these materials are magnetized, they become temporary or permanent magnets. Magnetite is a natural permanent magnet. | D: magnetism. |
What consists of the different species within an area?
Here are the choices:
A. biological community
B. contamination community
C. science community
D. abundant community | Community Ecology A biological community consists of the different species within an area, typically a three-dimensional space, and the interactions within and among these species. Community ecologists are interested in the processes driving these interactions and their consequences. Questions about conspecific interactions often focus on competition among members of the same species for a limited resource. Ecologists also study interactions among various species; members of different species are called heterospecifics. Examples of heterospecific interactions include predation, parasitism, herbivory, competition, and pollination. These interactions can have regulating effects on population sizes and can impact ecological and evolutionary processes affecting diversity. For example, Karner blue butterfly larvae form mutualistic relationships with ants. Mutualism is a form of a longterm relationship that has coevolved between two species and from which each species benefits. For mutualism to exist between individual organisms, each species must receive some benefit from the other as a consequence of the relationship. Researchers have shown that there is an increase in the probability of survival when Karner blue butterfly larvae (caterpillars) are tended by ants. This might be because the larvae spend less time in each life stage when tended by ants, which provides an advantage for the larvae. Meanwhile, the Karner blue butterfly larvae secrete a carbohydraterich substance that is an important energy source for the ants. Both the Karner blue larvae and the ants benefit from their interaction. | A: biological community. |
What do prevailing winds influence?
Here are the choices:
A. barometric pressure
B. temperature
C. climate
D. weather | Prevailing winds are the result of atmospheric circulation cells. They influence the climate of a region. | C: climate. |
What do you call a process that uses microorganisms to consume a pollutant?
Here are the choices:
A. filtration
B. bioremediation
C. siltation
D. biodegradation | Cleaning groundwater in an aquifer requires bioremediation or chemical remediation. Bioremediation uses microorganisms to consume a pollutant. Chemical remediation destroys the contaminant. | B: bioremediation. |
What is the term for a disturbance in matter that causes the transfer of energy from place to place?
Here are the choices:
A. flooding wave
B. mechanical wave
C. temperature wave
D. nucleation | A mechanical wave is a disturbance in matter that transfers energy from place to place. A mechanical wave starts when matter is disturbed. An example of a mechanical wave is pictured in Figure below . A drop of water falls into a pond. This disturbs the water in the pond. What happens next? The disturbance travels outward from the drop in all directions. This is the wave. A source of energy is needed to start a mechanical wave. In this case, the energy comes from the falling drop of water. | B: mechanical wave. |
Exemplified by cesium, which ignites spontaneously in air, pure elements with a high metallic character tend to be very what?
Here are the choices:
A. inactive
B. radiactive
C. reactive
D. proactive | Pure elements with a high metallic character, meaning those that have chemical properties most similar to properties of metals, are generally very reactive. Metals tend to lose electrons in chemical reactions, as indicated by their low ionization energies. Within a compound, metal atoms have a relatively low attraction to shared electrons, as indicated by their low electronegativity values. By following the trend summary in Figure below , you can see that the most reactive metals would reside in the lower left portion of the periodic table. The most reactive metal that occurs naturally in reasonable quantities is cesium, which is always found in nature as a compound, never as a free element. It reacts explosively with water and will ignite spontaneously in air. Francium is below cesium in the alkali metal group, but it is so rare that many of its properties have never even been observed. | C: reactive. |
What is the term for the use of two or more lewis structures to represent the covalent bonding in a molecule?
Here are the choices:
A. harmony
B. reaction
C. resonance
D. frequency | Resonance is the use of two or more Lewis structures to represent the covalent bonding in a molecule. One of the valid structures is referred to as a resonance structure. It is now understood that the true structure of a molecule which displays resonance is that of an average or a hybrid of all the resonance structures. In the case of the O 3 molecule, each of the covalent bonds between O atoms is best thought of as being “one and a half” bonds, as opposed to either a pure single bond or a pure double bond. This “half-bond” can be shown as a dotted line in both the Lewis structure and the molecular model (see Figure below ). | C: resonance. |
All eukaryotic cells have mitochondria, but not all eukaryotic cells have what?
Here are the choices:
A. ribosomes
B. golgi bodies
C. chloroplasts
D. cytoplasm | Chapter 23 1 Figure 23.5 All eukaryotic cells have mitochondria, but not all eukaryotic cells have chloroplasts. 3 Figure 23.18 C 4 D 6 C 8 D 10 B 12 C 14 A 16 A 18 Eukaryotic cells arose through endosymbiotic events that gave rise to the energy-producing organelles within the eukaryotic cells such as mitochondria and chloroplasts. The nuclear genome of eukaryotes is related most closely to the Archaea, so it may have been an early archaean that engulfed a bacterial cell that evolved into a mitochondrion. Mitochondria appear to have originated from an alpha-proteobacterium, whereas chloroplasts originated as a cyanobacterium. There is also evidence of secondary endosymbiotic events. Other cell components may also have resulted from endosymbiotic events. 20 As an intestinal parasite, Giardia cysts would be exposed to low pH in the stomach acids of its host. To survive this environment and reach the intestine, the cysts would have to be resistant to acidic conditions. 22 By definition, an obligate saprobe lacks the ability to perform photosynthesis, so it cannot directly obtain nutrition by searching for light. Instead, a chemotactic mechanism that senses the odors released during decay might be a more effective sensing organ for a saprobe. 24 The trypanosomes that cause this disease are capable of expressing a glycoprotein coat with a different molecular structure with each generation. Because the immune system must respond to specific antigens to raise a meaningful defense, the changing nature of trypanosome antigens prevents the immune system from ever clearing this infection. Massive trypanosome infection eventually leads to host organ failure and death. | C: chloroplasts. |
Which part of the body of amphibians, easily absorbs substances from the environment?
Here are the choices:
A. liver
B. Eyes
C. skin
D. scales | Why are so many amphibian species threatened by extinction, and why should you care? The second question is easy. Amphibians control pests, may be a source of new medicines, and help feed many other animals. The nature of amphibian skin may help explain why so many amphibian species are at risk. Their skin easily absorbs substances from the environment, such as pollutants in water or air. Therefore, they may suffer from poor environmental quality before other animals do. As such, they may provide an early-warning system of environmental damage. | C: skin. |
What element do plants use to store energy as atp?
Here are the choices:
A. nitrogen
B. oxygen
C. carbon
D. chlorophyll | The next most abundant element in plant cells is nitrogen (N); it is part of proteins and nucleic acids. Nitrogen is also used in the synthesis of some vitamins. Hydrogen and oxygen are macronutrients that are part of many organic compounds, and also form water. Oxygen is necessary for cellular respiration; plants use oxygen to store energy in the form of ATP. Phosphorus (P), another macromolecule, is necessary to synthesize nucleic acids and phospholipids. As part of ATP, phosphorus enables food energy to be converted into chemical energy through oxidative phosphorylation. Likewise, light energy is converted into chemical energy during photophosphorylation in photosynthesis, and into chemical energy to be extracted during respiration. Sulfur is part of certain amino acids, such as cysteine and methionine, and is present in several coenzymes. Sulfur also plays a role in photosynthesis as part of the electron transport chain, where hydrogen gradients play a key role in the conversion of light energy into ATP. Potassium (K) is important because of its role in regulating stomatal opening and closing. As the openings for gas exchange, stomata help maintain a healthy water balance; a potassium ion pump supports this process. | B: oxygen. |
What is the term for the deepest places on earth?
Here are the choices:
A. the core
B. mines
C. tunnels
D. trenches | a deep hole in the seafloor where subduction takes place; trenches are the deepest places on Earth. | D: trenches. |
The posterior pituitary is an extension of what anatomical structure?
Here are the choices:
A. hypothalamus
B. frontal lobe
C. hippocampus
D. brain stem | A: hypothalamus. | |
What occurs when the cartilage at the ends of the bones breaks down?
Here are the choices:
A. rheumatism
B. osteoporosis
C. osteoarthritis
D. stress fracture | Osteoarthritis occurs when the cartilage at the ends of the bones breaks down. The break down of the cartilage leads to pain and stiffness in the joint. Decreased movement of the joint because of the pain may lead to weakening of the muscles that normally move the joint, and the ligaments surrounding the joint may become loose. Osteoarthritis is the most common form of arthritis . It has many contributing factors, including aging, sport injuries, fractures, and obesity. | C: osteoarthritis. |
What do the planets orbit around in the solar system?
Here are the choices:
A. the moon
B. the Earth
C. the Milky Way
D. the sun | In the solar system, the planets orbit around the Sun. The Sun and each of the planets of our solar system are round. Earth is the third planet from the Sun. It is one of the inner planets. Jupiter is an outer planet. It is the largest planet in the solar system at about 1,000 times the size of Earth. The Sun is about 1,000 times bigger than Jupiter! ( Figure below ). | D: the sun. |
Which period after birth has the most rapid growth?
Here are the choices:
A. adolescence
B. infancy
C. early childhood
D. middle childhood | Infancy is the period of most rapid growth after birth. Growth is even faster during infancy that it is during puberty. By the end of the first year, the average baby is twice as long as it was at birth and three times as heavy. | B: infancy. |
What does sexual reproduction with gametes and fertilization produce?
Here are the choices:
A. diploid sporophyte
B. identical twins
C. sister chromatids
D. haploid zygote | All plants have a characteristic life cycle that includes alternation of generations . Plants alternate between haploid and diploid generations. Alternation of generations allows for both asexual and sexual reproduction. Beginning with the diploid sporophyte , spores form from meiosis. Asexual reproduction with spores produces haploid individuals called gametophytes , which produce haploid gametes by mitosis. Sexual reproduction with gametes and fertilization produces the diploid sporophyte. A typical plant’s life cycle is diagrammed in Figure below . | A: diploid sporophyte. |
What keeps the earth orbiting the sun?
Here are the choices:
A. variation
B. inertia
C. gravity
D. speed | Every moment of every day is a field trip to gravity. Gravity is everywhere! You have a gravitational attraction to your dog. You have one to your pencil. You even have one to your school principal! These gravitational attractions are very small compared with the most important one you have. This is your gravitational attraction to Earth. It's what keeps you from floating off into space. Gravity holds our planet together. Gravity keeps Earth orbiting the Sun. We wouldn't be here without gravity. | C: gravity. |
The depth of the atmosphere is greatest where?
Here are the choices:
A. under water
B. the stratosphere
C. the ionosphere
D. sea level | The depth (distance from top to bottom) of the atmosphere is greatest at sea level and decreases at higher altitudes. With greater depth of the atmosphere, more air is pressing down from above. Therefore, air pressure is greatest at sea level and falls with increasing altitude. On top of Mount Everest, which is the tallest mountain on Earth, air pressure is only about one-third of the pressure at sea level. | D: sea level. |
The lungs, kidneys, skin, and large intestine are all part of what organ system?
Here are the choices:
A. respiratory
B. excretory
C. digestive
D. sensory | Organs of the excretory system include the kidneys, large intestine, skin, and lungs. | B: excretory. |
What is the male gamete called in humans?
Here are the choices:
A. dna
B. testes
C. egg
D. sperm | 27.1 | Anatomy and Physiology of the Male Reproductive System By the end of this section, you will be able to: • Describe the structure and function of the organs of the male reproductive system • Describe the structure and function of the sperm cell • Explain the events during spermatogenesis that produce haploid sperm from diploid cells • Identify the importance of testosterone in male reproductive function Unique for its role in human reproduction, a gamete is a specialized sex cell carrying 23 chromosomes—one half the number in body cells. At fertilization, the chromosomes in one male gamete, called a sperm (or spermatozoon), combine with the chromosomes in one female gamete, called an oocyte. The function of the male reproductive system (Figure 27.2) is to produce sperm and transfer them to the female reproductive tract. The paired testes are a crucial component in this process, as they produce both sperm and androgens, the hormones that support male reproductive physiology. In humans, the most important male androgen is testosterone. Several accessory organs and ducts aid the process of sperm maturation and transport the sperm and other seminal components to the penis, which delivers sperm to the female reproductive tract. In this section, we examine each of these different structures, and discuss the process of sperm production and transport. | D: sperm. |
The lifecycle of an ascomycete is characterized by the production of what during the sexual phase?
Here are the choices:
A. cerci
B. asci
C. flageli
D. abaci | Figure 24.13 The lifecycle of an ascomycete is characterized by the production of asci during the sexual phase. The haploid phase is the predominant phase of the life cycle. | B: asci. |
What does the concentration of a solution represent?
Here are the choices:
A. spending of solute
B. percentage of solute
C. the darkness
D. the percentage of contaminates | The concentration of a solution represents the percentage of the solution that is the solute. You can calculate the concentration of a solution using this formula:. | B: percentage of solute. |
What is the term for any behavior that occurs only after experience or practice?
Here are the choices:
A. practiced behavior
B. saved behavior
C. learned behavior
D. studied behavior | Learned behavior is any behavior that occurs only after experience or practice. The more intelligent a species is, the more it depends on learned behaviors, which have the advantage of being flexible. Ways in which animals learn behaviors include habituation, observational learning, conditioning, learning through play, and insight learning. | C: learned behavior. |
What do we call the movement of individuals into a population from other areas?
Here are the choices:
A. pilgrimage
B. assimilation
C. immigration
D. nomadic | Immigration is the movement of individuals into a population from other areas. This increases the population size and growth rate. | C: immigration. |
Enzymes, proteins, electron carriers, and pumps that play roles in glycolysis, the citric acid cycle, and the electron transport chain tend to catalyze reactions that are what?
Here are the choices:
A. changeable
B. non-reversible
C. reversible
D. continuous | Control of Catabolic Pathways Enzymes, proteins, electron carriers, and pumps that play roles in glycolysis, the citric acid cycle, and the electron transport chain tend to catalyze non-reversible reactions. In other words, if the initial reaction takes place, the pathway is committed to proceeding with the remaining reactions. Whether a particular enzyme activity is released depends upon the energy needs of the cell (as reflected by the levels of ATP, ADP, and AMP). Glycolysis The control of glycolysis begins with the first enzyme in the pathway, hexokinase (Figure 7.19). This enzyme catalyzes the phosphorylation of glucose, which helps to prepare the compound for cleavage in a later step. The presence of the negatively charged phosphate in the molecule also prevents the sugar from leaving the cell. When hexokinase is inhibited, glucose diffuses out of the cell and does not become a substrate for the respiration pathways in that tissue. The product of the hexokinase reaction is glucose-6-phosphate, which accumulates when a later enzyme, phosphofructokinase, is inhibited. | B: non-reversible. |
Is purifying water a simple or complicated process?
Here are the choices:
A. simple
B. expensive
C. complicated
D. impossible | Purification of water for drinking and other uses is a complicated process. Heavy metals need to be removed, a process accomplished by addition of carbonates and sulfates. Lead contamination can present major health problems, especially for younger children. Lead sulfates and carbonates are very insoluble, so will precipitate out of solution very easily. | C: complicated. |
What is a sac-like organ at the end of the esophagus?
Here are the choices:
A. spleen
B. appendix
C. larynx
D. the stomach | The stomach is a sac-like organ at the end of the esophagus. It has thick muscular walls that contract and relax to squeeze and mix food. This helps break the food into smaller pieces. It also helps mix the food with enzymes and other secretions in the stomach. For example, the stomach secretes the enzyme pepsin, which helps digest proteins. | D: the stomach. |
Substances may be either elements or what?
Here are the choices:
A. pure compounds
B. existent compounds
C. pure chemicals
D. fundamental compounds | Substances may be either elements or pure compounds. They may also be solid, liquid, or gas. Some of the elements (such as silver) exist in the solid form. Other elements (mercury) exist as liquids at room temperature. Elements such as helium and radon exist as gases at room temperature. A compound such as water will take the form of a solid, a liquid, or a gas, depending upon the temperature. | A: pure compounds. |
Visible light can be split into colors with the use of a what?
Here are the choices:
A. kaleidoscope
B. convex lenses
C. prism
D. spectrum | The Figure above shows how the electromagnetic spectrum displays a wide variation in wavelength and frequency. Radio waves have wavelengths of as long as hundreds of meters, while the wavelength of gamma rays are on the order of 10 -12 m. The corresponding frequencies range from 10 6 to 10 21 Hz. Visible light can be split into colors with the use of a prism ( Figure below ), yielding the visible spectrum of light. Red light has the longest wavelength and lowest frequency, while violet light has the shortest wavelength and highest frequency. Visible light wavelength ranges from about 400 – 700 nm with frequencies in the range of 10 14 Hz. | C: prism. |
Marshes, swamps, and bogs are types of what?
Here are the choices:
A. grasslands
B. rivers
C. ponds
D. wetlands | Not all wetlands are alike, as you can see from Figure below . Wetlands vary in how wet they are and how much of the year they are soaked. Wetlands also vary in the kinds of plants that live in them. This depends mostly on the climate where the wetland is found. Types of wetlands include marshes, swamps, and bogs. | D: wetlands. |
What is the chief organ of the urinary system?
Here are the choices:
A. liver
B. bladder
C. kidney
D. lung | The kidneys are the chief organs of the urinary system. | C: kidney. |
What type of winds blow over a limited area?
Here are the choices:
A. gales
B. local winds
C. trade winds
D. hurricanes | Local winds are winds that blow over a limited area. They are influenced by local geography, such as nearness to an ocean. They include land and sea breezes as well as monsoons. | B: local winds. |
In terms of scientific investigation, things you notice about an environment using your five senses are called what?
Here are the choices:
A. evidence
B. observations
C. patterns
D. behaviors | Imagine that you are a scientist. While collecting water samples at a local pond, you notice a frog with five legs instead of four ( Figure below ). As you start to look around, you discover that many of the frogs have extra limbs, extra eyes, or no eyes. One frog even has limbs coming out of its mouth. These are your observations , or things you notice about an environment using your five senses. | B: observations. |
What is the final product of the calvin cycle?
Here are the choices:
A. glucose
B. insulin
C. energy
D. chloride | The reactions of the Calvin cycle add carbon (from carbon dioxide in the atmosphere) to a simple five-carbon molecule called RuBP. These reactions use chemical energy from NADPH and ATP that were produced in the light reactions. The final product of the Calvin cycle is glucose. | A: glucose. |
The nail bed is a specialized structure of the epidermis that is found at the tips of our what?
Here are the choices:
A. only fingers
B. fingers, nails, and scalp
C. fingers and toes
D. only nails | Nails The nail bed is a specialized structure of the epidermis that is found at the tips of our fingers and toes. The nail body is formed on the nail bed, and protects the tips of our fingers and toes as they are the farthest extremities and the parts of the body that experience the maximum mechanical stress (Figure 5.13). In addition, the nail body forms a back-support for picking up small objects with the fingers. The nail body is composed of densely packed dead keratinocytes. The epidermis in this part of the body has evolved a specialized structure upon which nails can form. The nail body forms at the nail root, which has a matrix of proliferating cells from the stratum basale that enables the nail to grow continuously. The lateral nail fold overlaps the nail on the sides, helping to anchor the nail body. The nail fold that meets the proximal end of the nail body forms the nail cuticle, also called the eponychium. The nail bed is rich in blood vessels, making it appear pink, except at the base, where a thick layer of epithelium over the nail matrix forms a crescent-shaped region called the lunula (the “little moon”). The area beneath the free edge of the nail, furthest from the cuticle, is called the hyponychium. It consists of a thickened layer of stratum corneum. | C: fingers and toes. |
The anatomical arrangement of capillaries and alveoli emphasizes the structural and functional relationship of what systems?
Here are the choices:
A. respiratory and circulatory
B. digestive and respiratory
C. nervous and lymphatic
D. endocrine and renal | are attached to the end of each bronchiole. At the end of each duct are approximately 100 alveolar sacs, each containing 20 to 30 alveoli that are 200 to 300 microns in diameter. Gas exchange occurs only in alveoli. Alveoli are made of thin-walled parenchymal cells, typically one-cell thick, that look like tiny bubbles within the sacs. Alveoli are in direct contact with capillaries (one-cell thick) of the circulatory system. Such intimate contact ensures that oxygen will diffuse from alveoli into the blood and be distributed to the cells of the body. In addition, the carbon dioxide that was produced by cells as a waste product will diffuse from the blood into alveoli to be exhaled. The anatomical arrangement of capillaries and alveoli emphasizes the structural and functional relationship of the respiratory and circulatory systems. Because there are so many alveoli (~300 million per lung) within each alveolar sac and so many sacs at the end of each alveolar duct, the lungs have a sponge-like consistency. This organization produces a very large surface area that is available for gas exchange. The surface area of alveoli in the lungs is approximately 75 m2. This large surface area, combined with the thin-walled nature of the alveolar parenchymal cells, allows gases to easily diffuse across the cells. | A: respiratory and circulatory. |
What term describes all but the sex chromosomes?
Here are the choices:
A. lysosomes
B. telomeres
C. sporozoans
D. autsomes | Animals and most plants have two special chromosomes. They are called sex chromosomes . These are chromosomes that determine the sex of the organism. All of the other chromosomes are called autosomes . Genes on sex chromosomes may be inherited differently than genes on autosomes. | D: autsomes. |
The sun and all objects held by it's gravity make up the?
Here are the choices:
A. atmosphere
B. planet
C. milky way
D. solar system | The Sun and all the objects held by its gravity make up the solar system. | D: solar system. |
From the uterus, where do sperm travel next?
Here are the choices:
A. fallopian tubes
B. urinary tract
C. vagina
D. ovaries | A day or two after an ovary releases an egg, the egg may unite with a sperm. Sperm are deposited in the vagina during sexual intercourse. They propel themselves through the uterus and enter a fallopian tube. This is where fertilization usually takes place. | A: fallopian tubes. |
What completes the process as undigested material passes out of the digestive system?
Here are the choices:
A. reaction
B. elimination
C. accumulation
D. culmination | B: elimination. | |
What is a thin layer of gas that surrounds earth called?
Here are the choices:
A. the wind cycle
B. the cloud cover
C. the dioxide
D. the atmosphere | The atmosphere is a thin layer of gas that surrounds Earth. Climatologists study the atmosphere. These scientists work to understand the climate as it is now. They also study how climate will change in response to global warming. | D: the atmosphere. |
What does all matter consist of?
Here are the choices:
A. oxygen
B. helium
C. carbon
D. atoms | All matter consists of atoms, which cannot be further subdivided into smaller particles. | D: atoms. |
What do you call a system that has one or more planets orbiting one or more stars?
Here are the choices:
A. solar system
B. galaxy
C. atom
D. molecular system | Since the early 1990s, astronomers have discovered other solar systems. A solar system has one or more planets orbiting one or more stars. We call these planets “extrasolar planets,” or exoplanets . They are called exoplanets because they orbit a star other than the Sun. As of April 2014, more than 4,600 exoplanets have been found, with 1706 confirmed. The rate of discovery is increasing rapidly! You can check out how many we have found at http://planetquest. jpl. nasa. gov/ . | A: solar system. |
The longest period of daylight hours occurs at the beginning of what season?
Here are the choices:
A. autumn
B. spring
C. winter
D. summer | D: summer. | |
H2o is the chemical formula for what?
Here are the choices:
A. water
B. salt
C. smog
D. glass | Suppose that you wanted to know how many hydrogen atoms were in a mole of water molecules. First, you would need to know the chemical formula for water, which is H 2 O. There are two atoms of hydrogen in each molecule of water. How many atoms of hydrogen would there be in two water molecules? There would be 2 × 2 = 4 hydrogen atoms. How about in a dozen? In that case a dozen is 12 so 12 × 2 = 24 hydrogen atoms in a dozen water molecules. To get the answers, (4 and 24) you had to multiply the given number of molecules by two atoms of hydrogen per molecule. So to find the number of hydrogen atoms in a mole of water molecules, the problem could be solved using conversion factors. | A: water. |
What occurs when light interacts with our atmosphere?
Here are the choices:
A. eclipse
B. prism effect
C. rainbow formation
D. rayleigh scattering | Rayleigh scattering occurs when light interacts with our atmosphere. The shorter the wavelength of light, the more strongly it is disturbed by collisions with atmospheric molecules. So blue light from the Sun is preferentially scattered by these collisions into our line of sight. This is why the sky appears blue. | D: rayleigh scattering. |
Layers of placental transfer cells help transport nutrients to the embryos as they develop into what?
Here are the choices:
A. kinesins
B. keratinocytes
C. sporophytes
D. fibroblasts | C: sporophytes. | |
The kayak’s motion in the water is an example of classical addition of what?
Here are the choices:
A. force
B. acceleration
C. velocities
D. momentum | If you’ve ever seen a kayak move down a fast-moving river, you know that remaining in the same place would be hard. The river current pulls the kayak along. Pushing the oars back against the water can move the kayak forward in the water, but that only accounts for part of the velocity. The kayak’s motion is an example of classical addition of velocities. In classical physics, velocities add as vectors. The kayak’s velocity is the vector sum of its velocity relative to the water and the water’s velocity relative to the riverbank. | C: velocities. |
Introduction genetics is the study of what?
Here are the choices:
A. biology
B. variability
C. heredity
D. obesity | Introduction Genetics is the study of heredity. Johann Gregor Mendel set the framework for genetics long before chromosomes or genes had been identified, at a time when meiosis was not well understood. Mendel selected a simple biological system and conducted methodical, quantitative analyses using large sample sizes. Because of Mendel’s work, the fundamental principles of heredity were revealed. We now know that genes, carried on chromosomes, are the basic functional units of heredity with the ability to be replicated, expressed, or mutated. Today, the postulates put forth by Mendel form the basis of classical, or Mendelian, genetics. Not all genes are transmitted from parents to offspring according to Mendelian genetics, but Mendel’s experiments serve as an excellent starting point for thinking about inheritance. | C: heredity. |
A _______ of biology is a fundamental concept that is just as true for a bee or a sunflower as it is for us.
Here are the choices:
A. hypothesis
B. principle
C. notion
D. theory | The word principle can be defined as "a fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning. " A principle of biology is a fundamental concept that is just as true for a bee or a sunflower as it is for us. All life, including that sunflower and bee, is made of at least one cell. The traits of a particular organism are embedded within its genes, that organism must maintain homeostasis to survive, and that organism has evolved from previously existing species. | B: principle. |
Ionic liquids heating a salt to its melting point produces a what?
Here are the choices:
A. gas
B. molten salt
C. table salt
D. plasma | Molten Salts and Ionic Liquids Heating a salt to its melting point produces a molten salt. If we heated a sample of solid NaCl to its melting point of 801°C, for example, it would melt to give a stable liquid that conducts electricity. The characteristics of molten salts other than electrical conductivity are their high heat capacity, ability to attain very high temperatures (over 700°C) as a liquid, and utility as solvents because of their relatively low toxicity. Molten salts have many uses in industry and the laboratory. For example, in solar power towers in the desert of California, mirrors collect and focus sunlight to melt a mixture of sodium nitrite and sodium nitrate. The heat stored in the molten salt is used to produce steam that drives a steam turbine and a generator, thereby producing electricity from the sun for southern California. Due to their low toxicity and high thermal efficiency, molten salts have also been used in nuclear reactors to enable operation at temperatures greater than 750°C. One prototype reactor tested in the 1950s used a fuel and a coolant consisting of molten fluoride salts, including NaF, ZrF 4, and UF4. Molten salts are also. | B: molten salt. |
What is the term for the temperature at which a solid changes into a liquid?
Here are the choices:
A. the starting point
B. the melting point
C. the mixture point
D. the pressure point | The melting point is the temperature at which a solid changes into a liquid. | B: the melting point. |
What does glycolysis generate in phase ii?
Here are the choices:
A. amino acids
B. adp
C. atp
D. dna | Steps in Glycolysis The 10 reactions of glycolysis, summarized in Figure 20.16 "Glycolysis", can be divided into two phases. In the first 5 reactions—phase I—glucose is broken down into two molecules of glyceraldehyde 3-phosphate. In the last five reactions—phase II—each glyceraldehyde 3-phosphate is converted into pyruvate, and ATP is generated. Notice that all the intermediates in glycolysis are phosphorylated and contain either six or three carbon atoms. Figure 20.16 Glycolysis. | C: atp. |
These vacuoles take water from the cytoplasm and excrete it from the cell to avoid bursting due to what?
Here are the choices:
A. impervious pressure
B. static pressure
C. osmotic pressure
D. apoptotic pressure | Vacuoles are membrane-bound organelles that can have secretory, excretory, and storage functions. Vacuoles are usually much larger than vesicles. Many organisms will use vacuoles as storage areas and some plant cells have very large vacuoles. The large central vacuole of the plant cell is used for osmotic control (storage of water) and nutrient storage. Contractile vacuoles are found in certain protists. These vacuoles take water from the cytoplasm and excrete it from the cell to avoid bursting due to osmotic pressure. | C: osmotic pressure. |
Where does the purple color in quartz come from?
Here are the choices:
A. aluminum
B. bronze
C. iron
D. dirt | A certain mineral may form in different colors. Figure below shows four samples of quartz, including one that is colorless and one that is purple. The purple color comes from a tiny amount of iron. The iron in quartz is a chemical impurity. Iron is not normally found in quartz. Many minerals are colored by chemical impurities. Other factors can also affect a mineral’s color. Weathering changes the surface of a mineral. Because color alone is unreliable, geologists rarely identify a mineral just on its color. To identify most minerals, they use several properties. | C: iron. |
What is the largest part of the brain?
Here are the choices:
A. hypothalamus
B. pituitary gland
C. cerebrum
D. temporal lobe | The cerebrum is the largest part of the brain. It sits on top of the brain stem. The cerebrum controls functions that we are aware of, such as problem-solving and speech. It also controls voluntary movements, like waving to a friend. Whether you are doing your homework or jumping hurdles, you are using your cerebrum. | C: cerebrum. |
Data from paleontology offer insights into the early evolution of what?
Here are the choices:
A. acids
B. cells
C. fungi
D. neurons | C: fungi. | |
One crystalline form of calcium carbonate is the mineral sold as what?
Here are the choices:
A. basalt
B. quartz
C. salt
D. calcite | In our calculation, we have ignored the reaction of the weakly basic anion with water, which tends to make the actual solubility of many salts greater than the calculated value. Exercise One crystalline form of calcium carbonate (CaCO3) is the mineral sold as “calcite” in mineral and gem shops. The solubility of calcite in water is 0.67 mg/100 mL. Calculate its Ksp. Answer: 4.5 × 10−9. | D: calcite. |
Human evolution shows that evolutionary changes typically occur at what pace?
Here are the choices:
A. rapid
B. sudden
C. slow
D. uneven | Usually evolutionary changes occur at a very slow pace. Human evolution took millions of years. However, sometimes evolution can also happen quite quickly. | C: slow. |
When bacteria enter the bloodstream, the result is what condition?
Here are the choices:
A. septicemia
B. hypoxia
C. diarrhea
D. hypertension | Most UTIs are not serious, but some infections can lead to serious problems. Long lasting kidney infections can cause permanent damage, including kidney scars, poor kidney function, high blood pressure, and other problems. Some sudden kidney infections can be life threatening, especially if the bacteria enter the bloodstream, a condition called septicemia. | A: septicemia. |
Solid-state radiation detectors convert ionization produced in a semiconductor (like those found in computer chips) directly into what?
Here are the choices:
A. thermal energy
B. microwaves
C. isotopes
D. electrical signal | Solid-state radiation detectors convert ionization produced in a semiconductor (like those found in computer chips) directly into an electrical signal. Semiconductors can be constructed that do not conduct current in one particular direction. When a voltage is applied in that direction, current flows only when ionization is produced by radiation, similar to what happens in a Geiger tube. Further, the amount of current in a solid-state detector is closely related to the energy deposited and, since the detector is solid, it can have a high efficiency (since ionizing radiation is stopped in a shorter distance in solids fewer particles escape detection). As with scintillators, very sophisticated information can be obtained from solid-state detectors. PhET Explorations: Radioactive Dating Game Learn about different types of radiometric dating, such as carbon dating. Understand how decay and half life work to enable radiometric dating to work. Play a game that tests your ability to match the percentage of the dating element that remains to the age of the object. | D: electrical signal. |
Most, if not all, of the extant animal phyla today evolved during the cambrian period, yet many of what devastating events have taken place since then?
Here are the choices:
A. life extinctions
B. earthquakes
C. starvations
D. mass extinctions | Describe at least two major changes to the animal phylogenetic tree that have come about due to molecular or genetic findings. How is it that morphological data alone might lead scientists to group animals into erroneous evolutionary relationships? 26. Briefly describe at least two theories that attempt to explain the cause of the Cambrian explosion. How is it that most, if not all, of the extant animal phyla today evolved during the Cambrian period if so many massive extinction events have taken place since then?. | D: mass extinctions. |
What is the name for the energy required for an electron to be added to a neutral atom in its gaseous form?
Here are the choices:
A. electron affinity
B. mass affinity
C. photon affinity
D. neutron affinity | Electron affinity is the energy required for an electron to be added to a neutral atom in its gaseous form. Because most atoms release energy when an electron is added, most electron affinity values are negative. These values generally become more negative (more energy is released) as you move left to right across the table or from bottom to top. | A: electron affinity. |
Carbon atoms have six neutrons as well as how many protons?
Here are the choices:
A. two
B. four
C. six
D. ten | A neutron is a particle in the nucleus of an atom that has no electric charge. Atoms of an element often have the same number of neutrons as protons. For example, most carbon atoms have six neutrons as well as six protons. This is also shown in Figure below . | C: six. |
What term means that only molecules or ions of a certain size, shape, polarity or charge are capable of passing through the material?
Here are the choices:
A. selective permeation
B. radiation permeation
C. classic permeation
D. induced permeation | Osmosis and Osmotic Pressure of Solutions A number of natural and synthetic materials exhibit selective permeation, meaning that only molecules or ions of a certain size, shape, polarity, charge, and so forth, are capable of passing through (permeating) the material. Biological cell membranes provide elegant examples of selective permeation in nature, while dialysis tubing used to remove metabolic wastes from blood is a more simplistic technological example. Regardless of how they may be fabricated, these materials are generally referred to as semipermeable membranes. Consider the apparatus illustrated in Figure 11.25, in which samples of pure solvent and a solution are separated by a membrane that only solvent molecules may permeate. Solvent molecules will diffuse across the membrane in both directions. Since the concentration of solvent is greater in the pure solvent than the solution, these molecules will diffuse from the solvent side of the membrane to the solution side at a faster rate than they will in the reverse direction. The result is a net transfer of solvent molecules from the pure solvent to the solution. Diffusion-driven transfer of solvent molecules through a semipermeable membrane is a process known as osmosis. | A: selective permeation. |
What holds together the small molecules called nucleotides which make up nucleic acids?
Here are the choices:
A. permanent bonds
B. covalent bonds
C. curvature bonds
D. dissonance bonds | Nucleic acids consist of chains of small molecules called nucleotides, which are held together by covalent bonds. | B: covalent bonds. |
What type of cell contains a nucleus?
Here are the choices:
A. eukaryotic cell
B. chloroplasts cell
C. candid cell
D. endogenous cell | Eukaryotic cells contain a nucleus and several other types of organelles. These structures are involved in many vital cell functions. | A: eukaryotic cell. |
What method uses a retailer's coding method to catalog biological specimens in museums?
Here are the choices:
A. structure barcoding
B. content barcoding
C. metallic barcoding
D. dna barcoding | Measuring Biodiversity The technology of molecular genetics and data processing and storage are maturing to the point where cataloguing the planet’s species in an accessible way is close to feasible. DNA barcoding is one molecular genetic method, which takes advantage of rapid evolution in a mitochondrial gene present in eukaryotes, excepting the plants, to identify species using the sequence of portions of the gene. Plants may be barcoded using a combination of chloroplast genes. Rapid mass sequencing machines make the molecular genetics portion of the work relatively inexpensive and quick. Computer resources store and make available the large volumes of data. Projects are currently underway to use DNA barcoding to catalog museum specimens, which have already been named and studied, as well as testing the method on less studied groups. As of mid 2012, close to 150,000 named species had been barcoded. Early studies suggest there are significant numbers of undescribed species that looked too much like sibling species to previously be recognized as different. These now can be identified with DNA barcoding. Numerous computer databases now provide information about named species and a framework for adding new species. However, as already noted, at the present rate of description of new species, it will take close to 500 years before the complete catalog of life is known. Many, perhaps most, species on the planet do not have that much time. There is also the problem of understanding which species known to science are threatened and to what degree they are threatened. This task is carried out by the non-profit IUCN which, as previously mentioned, maintains the Red List—an online listing of endangered species categorized by taxonomy, type of threat, and other criteria (Figure 47.16). The Red List is supported by scientific research. In 2011, the list contained 61,000 species, all with supporting documentation. | D: dna barcoding. |
The level of carbon dioxide in the atmosphere is greatly influenced by the reservoir of carbon where?
Here are the choices:
A. before the oceans
B. after the oceans
C. in the oceans
D. in the earth | As stated, the atmosphere is a major reservoir of carbon in the form of carbon dioxide that is essential to the process of photosynthesis. The level of carbon dioxide in the atmosphere is greatly influenced by the reservoir of carbon in the oceans. The exchange of carbon between the atmosphere and water reservoirs influences how much carbon is found in each, and each one affects the other reciprocally. Carbon dioxide (CO2) from the atmosphere dissolves in water and, unlike oxygen and nitrogen gas, reacts with water molecules to form ionic compounds. Some of these ions combine with calcium ions in the seawater to form calcium carbonate (CaCO3), a major component of the shells of marine organisms. These organisms eventually form sediments on the ocean floor. Over geologic time, the calcium carbonate forms limestone, which comprises the largest carbon reservoir on Earth. On land, carbon is stored in soil as organic carbon as a result of the decomposition of living organisms or from weathering of terrestrial rock and minerals. Deeper under the ground, at land and at sea, are fossil fuels, the anaerobically decomposed remains of plants that take millions of years to form. Fossil fuels are considered a non-renewable resource because their use far exceeds their rate of formation. A non-renewable resource is either regenerated very slowly or not at all. Another way for carbon to enter the atmosphere is from land (including land beneath the surface of the ocean) by the eruption of volcanoes and other geothermal systems. Carbon sediments from the ocean floor are taken deep within Earth by the process of subduction: the movement of one tectonic plate beneath another. Carbon is released as carbon dioxide when a volcano erupts or from volcanic hydrothermal vents. Carbon dioxide is also added to the atmosphere by the animal husbandry practices of humans. The large number of land animals raised to feed Earth’s growing human population results in increased carbon-dioxide levels in the atmosphere caused by their respiration. This is another example of how human activity indirectly affects biogeochemical cycles in a significant way. Although much of the debate about the future effects of increasing atmospheric carbon on climate change focuses on fossils fuels, scientists take natural processes, such as volcanoes, plant growth, soil carbon levels, and respiration, into account as they model and predict the future impact of this increase. | C: in the oceans. |
Who controls prey population?
Here are the choices:
A. bees
B. parasites
C. predators
D. ecosystems | C: predators. | |
In which organs does gas exchange take place between blood and air?
Here are the choices:
A. kidneys
B. liver and spleen
C. lungs
D. esophagus and larynx | Respiration begins with ventilation . This is the process of moving air in and out of the lungs. The lungs are the organs in which gas exchange takes place between blood and air. | C: lungs. |
The frequency of sound waves is measured in what unit?
Here are the choices:
A. decibel
B. watt
C. hertz
D. rads | The frequency of sound waves is measured in hertz (Hz), or the number of waves that pass a fixed point in a second. Human beings can normally hear sounds with a frequency between about 20 Hz and 20,000 Hz. Sounds with frequencies below 20 hertz are called infrasound . Infrasound is too low-pitched for humans to hear. Sounds with frequencies above 20,000 hertz are called ultrasound . Ultrasound is too high-pitched for humans to hear. | C: hertz. |
Does an increase in temperature speed up or slow down reactions?
Here are the choices:
A. slow down
B. remain the same
C. end reaction
D. speed up | D: speed up. | |
An obstacle or opening that is shorter than the wavelength causes greater diffraction of what?
Here are the choices:
A. particles
B. waves
C. tides
D. ranges | An obstacle or opening that is shorter than the wavelength causes greater diffraction of waves. | B: waves. |
Corals build hard exoskeletons that grow to become coral what?
Here are the choices:
A. beds
B. reefs
C. crystals
D. layers | Cnidarians are aquatic invertebrates in Phylum Cnidaria. They include jellyfish and corals, both of which have radial symmetry. All cnidarians have nematocysts, and many are bioluminescent. They may exist in medusa and/or polyp form. Corals build hard exoskeletons that grow to become coral reefs. | B: reefs. |
What is the name of the procedure where an unknown compound can be analyzed in the laboratory in order to determine the percentages of each element contained within it?
Here are the choices:
A. gaseous analysis
B. elemental analysis
C. electrical analysis
D. chemical analysis | In a procedure called elemental analysis , an unknown compound can be analyzed in the laboratory in order to determine the percentages of each element contained within it. These percentages can be transformed into the mole ratio of the elements, which leads to the empirical formula. The steps to be taken are outlined below. | B: elemental analysis. |
While spermatogenesis produces four haploid sperm cells, oogenesis produces one mature what?
Here are the choices:
A. ovum
B. datum
C. semen
D. egg | Spermatogenesis produces four haploid sperm cells, while oogenesis produces one mature ovum. | A: ovum. |
What are groups of tens to hundreds of thousands of stars held tightly together by gravity called?
Here are the choices:
A. elliptical clusters
B. galaxy
C. elongated clusters
D. globular clusters | Television broadcasts also use radio waves. Sounds are encoded with frequency modulation, and pictures are encoded with amplitude modulation. The encoded radio waves are broadcast from a TV tower like the one in Figure below . When the waves are received by television sets, they are decoded and changed back to sounds and pictures. | D: globular clusters. |
What is the general name for the homogeneous mixture that is formed when a solute dissolves in a solvent?
Here are the choices:
A. Combination
B. solution
C. Reaction
D. Dissolvant | A solution is a homogeneous mixture in which a solute dissolves in a solvent. Water is a very common solvent, especially in organisms. | B: solution. |
Life itself could not exist without what energy, which plays a vital role in photosynthesis?
Here are the choices:
A. magnetic energy
B. spin energy
C. time energy
D. light energy | Our lives are filled with light. Through vision, the most valued of our senses, light can evoke spiritual emotions, such as when we view a magnificent sunset or glimpse a rainbow breaking through the clouds. Light can also simply amuse us in a theater, or warn us to stop at an intersection. It has innumerable uses beyond vision. Light can carry telephone signals through glass fibers or cook a meal in a solar oven. Life itself could not exist without light’s energy. From photosynthesis in plants to the sun warming a cold-blooded animal, its supply of energy is vital. | D: light energy. |
What does power imply is happening to energy?
Here are the choices:
A. being transferred
B. being destroyed
C. is expanding
D. being created | Examples of Power Examples of power are limited only by the imagination, because there are as many types as there are forms of work and energy. (See Table 7.3 for some examples. ) Sunlight reaching Earth’s surface carries a maximum power of about 1.3 kilowatts per square meter (kW/m 2). A tiny fraction of this is retained by Earth over the long term. Our consumption rate of fossil fuels is far greater than the rate at which they are stored, so it is inevitable that they will be depleted. Power implies that energy is transferred, perhaps changing form. It is never possible to change one form completely into another without losing some of it as thermal energy. For example, a 60-W incandescent bulb converts only 5 W of electrical power to light, with 55 W dissipating into thermal energy. Furthermore, the typical electric power plant converts only 35 to 40% of its fuel into electricity. The remainder becomes a huge amount of thermal energy that must be dispersed as heat transfer, as rapidly as it is created. A coal-fired power 6 plant may produce 1000 megawatts; 1 megawatt (MW) is 10 W of electric power. But the power plant consumes chemical energy at a rate of about 2500 MW, creating heat transfer to the surroundings at a rate of 1500 MW. (See Figure 7.25. | A: being transferred. |
Because the masses of subatomic particles are so small, a new unit, called what, was defined?
Here are the choices:
A. particle mass unit
B. atomic mass unit
C. nuclear mass unit
D. atomic volume unit | Chadwick’s work resulted in a new understanding of the nucleus of the atom; it is comprised of both protons and neutrons. Because the masses of subatomic particles are so small, a new unit, called an atomic mass unit (amu), was defined. Protons and neutrons each have a mass of approximately one amu. The Table below describes the characteristics of the three subatomic particles we have discussed. | B: atomic mass unit. |
Which organ breaks down amino acids and toxins that are in the blood?
Here are the choices:
A. liver
B. kidney
C. small intestine
D. skin | The liver breaks down excess amino acids and toxins in the blood. | A: liver. |
Which compound has positively and negatively charged ends?
Here are the choices:
A. real compound
B. tumultuous compound
C. non-polar compound
D. polar compound | Salt isn’t the only solute that dissolves in water. In fact, so many things dissolve in water that water is sometimes called the universal solvent. Water is such a good solvent because it is a very polar compound. A polar compound has positively and negatively charged ends. Solutes that are also charged are attracted to the oppositely charged ends of water molecules. This allows the water molecules to pull the solute particles apart. | D: polar compound. |
What system of the body is responsible for producing hormones?
Here are the choices:
A. endocrine system
B. nervous system
C. regulatory system
D. homeostasis system | The blood also carries hormones, which are chemical messenger molecules produced by organs of the endocrine system, through your body. Hormones are produced in one area of your body and have an effect on another area. To get to that other area, they must travel through your blood. An example is the hormone adrenaline, produced by the adrenal glands on top of the kidneys. Adrenaline has multiple effects on the heart (it quickens the heart rate), on muscles and on the airway. | A: endocrine system. |
What happens to a substance in a liquid state when the temperate is lowed?
Here are the choices:
A. it solidifies
B. it dissipates
C. it melts
D. it evaporates | Under the right pressure conditions, lowering the temperature of a substance in the liquid state causes the substance to solidify. The opposite effect occurs if the temperature is increased. | A: it solidifies. |
Sublimation and deposition involve direct transitions between solid and gas without going through which state?
Here are the choices:
A. chemical
B. homeostasis
C. liquid
D. carbon | Sublimation and deposition involve direct transitions between solid and gas without going through the liquid state. | C: liquid. |
What is the process by which plants and animals increase in size?
Here are the choices:
A. grafting
B. splicing
C. reproduction
D. growth | D: growth. | |
Which glands sit atop the kidneys and are composed of an outer cortex and an inner medulla, all surrounded by a connective tissue capsule?
Here are the choices:
A. salivary
B. thyroid glands
C. gonads
D. adrenal | Figure 17.17 Adrenal Glands Both adrenal glands sit atop the kidneys and are composed of an outer cortex and an inner medulla, all surrounded by a connective tissue capsule. The cortex can be subdivided into additional zones, all of which produce different types of hormones. LM × 204. (Micrograph provided by the Regents of University of Michigan Medical School © 2012). | D: adrenal. |
What is it that surrounds cells and serve to keep the insides separated from the outsides?
Here are the choices:
A. abundant membranes
B. inner membranes
C. biological membranes
D. similar membranes | Membranes Biological membranes surround cells and serve to keep the insides separated from the outsides. They are formed of phospholipid bilayer1 s, which by definition are a double layer of fatty acid2 molecules (mostly phospholipid3 s, lipids containing lots of phosphorus). Proteins4 serve very important functions in cellular membranes. They are active transports in and out of the cell, acting as gatekeepers. They relay signals in and out of the cell. Proteins are the site of many enzymatic reactions in the cell, and play a role in regulation of cellular processes. | C: biological membranes. |
What is the gland in the chest behind the breast bone that stores some types of lymphocytes while they mature?
Here are the choices:
A. thymus
B. pineal
C. Montgomery
D. lumbar | The thymus gland is in the chest behind the breast bone. It stores some types of lymphocytes while they mature. | A: thymus. |
What promotes cell division and are necessary for growing plants in tissue culture?
Here are the choices:
A. polyamines
B. cytokinins
C. mitochondria
D. auxins | Cytokinins promote cell division and are necessary for growing plants in tissue culture. A small piece of a plant is placed in sterile conditions to regenerate a new plant. | B: cytokinins. |
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