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The transfer of energy by electromagnetic waves is called what?
|
[
"electromagnetic radiation",
"particulate radiation",
"magnetic radiation",
"mechanical radiation"
] |
A
|
Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. Like other waves, electromagnetic waves transfer energy from one place to another. The transfer of energy by electromagnetic waves is called electromagnetic radiation . Electromagnetic waves can transfer energy through matter or across empty space. For an excellent video introduction to electromagnetic waves, go to this URL: http://www. youtube. com/watch?v=cfXzwh3KadE.
|
validation
|
sciq
| null |
The noble gases are unreactive because of their?
|
[
"carbon content",
"electron configurations",
"proton configurations",
"cell configurations"
] |
B
|
The noble gases are unreactive because of their electron configurations. The noble gas neon has the electron configuration of 1 s 2 2 s 2 2 p 6 . It has a full outer shell and cannot incorporate any more electrons into the valence shell. The other noble gases have the same outer shell electron configuration even though they have different numbers of inner-shell electrons.
|
validation
|
sciq
| null |
Some birds, such as gulls and terns and other waterfowl have what type of feet used for swimming or floating?
|
[
"bipedal",
"quad toed",
"webbed",
"lobed"
] |
C
|
Bird feet can also vary greatly among different birds. Some birds, such as gulls and terns and other waterfowl, have webbed feet used for swimming or floating ( Figure below ). Other birds, such as herons, gallinules, and rails, have four long spreading toes, which are adapted for walking delicately in the wetlands ( Figure below ). You can predict how the beaks and feet of birds will look depending on where they live and what type of food they eat. Flightless birds also have long legs that are adapted for running. Flightless birds include the ostrich and kiwi.
|
validation
|
sciq
| null |
Bones are considered organs because they contain what, specifically?
|
[
"calcium",
"blood",
"tissue",
"DNA"
] |
C
|
Bone Tissue Bones are considered organs because they contain various types of tissue, such as blood, connective tissue, nerves, and bone tissue. Osteocytes, the living cells of bone tissue, form the mineral matrix of bones. There are two types of bone tissue: compact and spongy. Compact Bone Tissue Compact bone (or cortical bone) forms the hard external layer of all bones and surrounds the medullary cavity, or bone marrow. It provides protection and strength to bones. Compact bone tissue consists of units called osteons or Haversian systems. Osteons are cylindrical structures that contain a mineral matrix and living osteocytes connected by canaliculi, which transport blood. They are aligned parallel to the long axis of the bone. Each osteon consists of lamellae, which are layers of compact matrix that surround a central canal called the Haversian canal. The Haversian canal (osteonic canal) contains the bone’s blood vessels and nerve fibers (Figure 38.19). Osteons in compact bone tissue are aligned in the same direction along lines of stress and help the bone resist bending or fracturing. Therefore, compact bone tissue is prominent in areas of bone at which stresses are applied in only a few directions.
|
validation
|
sciq
| null |
Plants take in carbon dioxide and give off what?
|
[
"methane",
"nitrogen",
"chlorophyll",
"oxygen"
] |
D
|
validation
|
sciq
| null |
|
For a scientific theory to be valid, in what way should it be verified?
|
[
"optimally",
"directly",
"experimentally",
"systematically"
] |
C
|
For a scientific theory to be valid, it must be verified experimentally. Many parts of the string theory are currently untestable due to the large amount of energy that would be needed to carry out the necessary experiments as well as the high cost of conducting these experiments. Therefore string theory may not be tested in the foreseeable future. Some scientists have even questioned whether it deserves to be called a scientific theory because it is not falsifiable.
|
validation
|
sciq
| null |
For plants, the amount of water, sunlight, nutrients, and space to grow are the important resources, whereas in animals, important resources include food, water, shelter, nesting space, and this?
|
[
"mates",
"eggs",
"entertainment",
"pairs"
] |
A
|
Role of Intraspecific Competition The logistic model assumes that every individual within a population will have equal access to resources and, thus, an equal chance for survival. For plants, the amount of water, sunlight, nutrients, and space to grow are the important resources, whereas in animals, important resources include food, water, shelter, nesting space, and mates. In the real world, phenotypic variation among individuals within a population means that some individuals will be better adapted to their environment than others. The resulting competition for resources among population members of the same species is termed intraspecific competition. Intraspecific competition may not affect populations that are well below their carrying capacity, as resources are plentiful and all individuals can obtain what they need. However, as population size increases, this competition intensifies. In addition, the accumulation of waste products can reduce carrying capacity in an environment. Examples of Logistic Growth Yeast, a microscopic fungus used to make bread and alcoholic beverages, exhibits the classical S-shaped curve when grown in a test tube (Figure 19.6a). Its growth levels off as the population depletes the nutrients that are necessary for its growth. In the real world, however, there are variations to this idealized curve. Examples in wild populations include sheep and harbor seals (Figure 19.6b). In both examples, the population size exceeds the carrying capacity for short periods of time and then falls below the carrying capacity afterwards. This fluctuation in population size continues to occur as the population oscillates around its carrying capacity. Still, even with this oscillation, the logistic model is confirmed.
|
validation
|
sciq
| null |
Which is the main organ of the respiratory system?
|
[
"the mouth",
"the stomach",
"the lungs",
"the liver"
] |
C
|
When you think of the processes of breathing, the lungs probably come to mind. The lungs are the main organ of the respiratory system. However, many other organs are also needed for the process of respiration to take place.
|
validation
|
sciq
| null |
Why is runoff from artificial fertilizer harmful to the chesapeake bay ecosystem?
|
[
"starts combustion",
"causes erosion",
"leaks food",
"causes pollution"
] |
D
|
The Chesapeake Bay has long been valued as one of the most scenic areas on Earth; it is now in distress and is recognized as a declining ecosystem. In the 1970s, the Chesapeake Bay was one of the first ecosystems to have identified dead zones, which continue to kill many fish and bottom-dwelling species, such as clams, oysters, and worms. Several species have declined in the Chesapeake Bay due to surface water runoff containing excess nutrients from artificial fertilizer used on land. The source of the fertilizers (with high nitrogen and phosphate content) is not limited to agricultural practices. There are many nearby urban areas and more than 150 rivers and streams empty into the bay that are carrying fertilizer runoff from lawns and gardens. Thus, the decline of the Chesapeake Bay is a complex issue and requires the cooperation of industry, agriculture, and everyday homeowners. Of particular interest to conservationists is the oyster population; it is estimated that more than 200,000 acres of oyster reefs existed in the bay in the 1700s, but that number has now declined to only 36,000 acres. Oyster harvesting was once a major industry for Chesapeake Bay, but it declined 88 percent between 1982 and 2007. This decline was due not only to fertilizer runoff and dead zones but also to overharvesting. Oysters require a certain minimum population density because they must be in close proximity to reproduce. Human activity has altered the oyster population and locations, greatly disrupting the ecosystem. The restoration of the oyster population in the Chesapeake Bay has been ongoing for several years with mixed success. Not only do many people find oysters good to eat, but they also clean up the bay. Oysters are filter feeders, and as they eat, they clean the water around them. In the 1700s, it was estimated that it took only a few days for the oyster population to filter the entire volume of the bay. Today, with changed water conditions, it is estimated that the present population would take nearly a year to do the same job. Restoration efforts have been ongoing for several years by non-profit organizations, such as the Chesapeake Bay Foundation. The restoration goal is to find a way to increase population density so the oysters can reproduce more efficiently. Many disease-resistant varieties (developed at the Virginia Institute of Marine Science for the College of William and Mary) are now available and have been used in the construction of experimental oyster reefs. Efforts to clean and restore the bay by Virginia and Delaware have been hampered because much of the pollution entering the bay comes from other states, which stresses the need for inter-state cooperation to gain successful restoration.
|
validation
|
sciq
| null |
What system do trees need to transport nutrients?
|
[
"vascular",
"circulatory",
"passive transport membrane",
"photosynthetic system"
] |
A
|
The trees tower in the sky, while the mosses carpet the forest floor. Mosses, like the first plants, are restricted to life near the ground because they lack vascular system. Only with a vascular system can these trees transport sugars, nutrients, and water up and down their tall trunks. The evolution of the vascular system was a big step in the evolutionary history of plants.
|
validation
|
sciq
| null |
Food allergies, ulcers, and heartburn all affect what organ system?
|
[
"digestive system",
"skeletal system",
"lymphatic system",
"nervous system"
] |
A
|
Many diseases can affect the digestive system. Three of the most common diseases that affect the digestive system are food allergies, ulcers, and heartburn. Foodborne illnesses and food intolerance are also serious issues associated with the digestive system.
|
validation
|
sciq
| null |
Like ammonia, hydrazine is both a brønsted base and which other base?
|
[
"lewis base",
"dynamic base",
"unit base",
"floyd base"
] |
A
|
Like ammonia, hydrazine is both a Brønsted base and a Lewis base, although it is weaker than ammonia. It reacts with strong acids and forms two series of salts that contain the N 2 H 5 + and N 2 H 6 2+ ions, respectively. Some rockets use hydrazine as a fuel.
|
validation
|
sciq
| null |
What is the layman's term for a state in which external stimuli are received but not consciously perceived?
|
[
"sleep",
"dreaming",
"immunity",
"homeostasis"
] |
A
|
validation
|
sciq
| null |
|
What are the tiny, negatively charged particles in an atom that move around the positive nucleus at the center?
|
[
"protons",
"electrons",
"quarks",
"neutrons"
] |
B
|
Energy levels (also called electron shells) are fixed distances from the nucleus of an atom where electrons may be found. Electrons are tiny, negatively charged particles in an atom that move around the positive nucleus at the center. Energy levels are a little like the steps of a staircase. You can stand on one step or another but not in between the steps. The same goes for electrons. They can occupy one energy level or another but not the space between energy levels.
|
validation
|
sciq
| null |
Enzymes, antibodies, and muscle fiber are all types of what?
|
[
"carbohydrates",
"proteins",
"acids",
"lipids"
] |
B
|
Many important molecules in your body are proteins. Examples include enzymes, antibodies, and muscle fiber. Enzymes are a type of protein that speed up chemical reactions. They are known as "biological catalysts. " For example, your stomach would not be able to break down food if it did not have special enzymes to speed up the rate of digestion. Antibodies that protect you against disease are proteins. Muscle fiber is mostly protein ( Figure below ).
|
validation
|
sciq
| null |
What are formed by the loss of one or two electrons from an element?
|
[
"cations",
"isotopes",
"ions",
"amines"
] |
A
|
Cations are formed by the loss of one or two electrons from an element.
|
validation
|
sciq
| null |
Betelgeuse is an example of what "colorful" stage in the life of very massive stars?
|
[
"blue star",
"red supergiant",
"blue supergiant",
"white supergiant"
] |
B
|
A more massive star ends its life in a more dramatic way. Very massive stars become red supergiants, like Betelgeuse.
|
validation
|
sciq
| null |
What single word can be defined as the ability to cause change in matter and the ability to do work?
|
[
"explosion",
"job",
"gas",
"energy"
] |
D
|
The concept of energy was first introduced in the chapter "States of Matter," where it is defined as the ability to cause change in matter. Energy can also be defined as the ability to do work. Work is done whenever a force is used to move matter. When work is done, energy is transferred from one object to another. For example, when the batter in Figure below uses energy to swing the bat, she transfers energy to the bat. The moving bat, in turn, transfers energy to the ball. Like work, energy is measured in the joule (J), or newton·meter (N·m).
|
validation
|
sciq
| null |
Wearing clothes that trap air next to your body on a cold day helps you retain what type of energy?
|
[
"caloric energy",
"thermal energy",
"alumal energy",
"adjacent energy"
] |
B
|
One way to retain your own thermal energy on a cold day is to wear clothes that trap air. That’s because air, like other gases, is a poor conductor of thermal energy. The particles of gases are relatively far apart, so they don’t bump into each other or into other things as often as the more closely spaced particles of liquids or solids. Therefore, particles of gases have fewer opportunities to transfer thermal energy. Materials that are poor thermal conductors are called thermal insulators . Down-filled snowsuits, like those in the Figure below , are good thermal insulators because their feather filling traps a lot of air.
|
validation
|
sciq
| null |
How many steps are involved in blood clotting?
|
[
"five",
"two",
"six",
"three"
] |
D
|
Figure 18.14 Hemostasis (a) An injury to a blood vessel initiates the process of hemostasis. Blood clotting involves three steps. First, vascular spasm constricts the flow of blood. Next, a platelet plug forms to temporarily seal small openings in the vessel. Coagulation then enables the repair of the vessel wall once the leakage of blood has stopped. (b) The synthesis of fibrin in blood clots involves either an intrinsic pathway or an extrinsic pathway, both of which lead to a common pathway. (credit a: Kevin MacKenzie).
|
validation
|
sciq
| null |
What type of pressure is the amount of force that is exerted by gases in the air surrounding any given surface?
|
[
"gravitational",
"vapor",
"fluid",
"atmospheric"
] |
D
|
Pulmonary ventilation is dependent on three types of pressure: atmospheric, intra-alveolar, and interpleural. Atmospheric pressure is the amount of force that is exerted by gases in the air surrounding any given surface, such as the body. Atmospheric pressure can be expressed in terms of the unit atmosphere, abbreviated atm, or in millimeters of mercury (mm Hg). One atm is equal to 760 mm Hg, which is the atmospheric pressure at sea level. Typically, for respiration, other pressure values are discussed in relation to atmospheric pressure. Therefore, negative pressure is pressure lower than the atmospheric pressure, whereas positive pressure is pressure that it is greater than the atmospheric pressure. A pressure that is equal to the atmospheric pressure is expressed as zero. Intra-alveolar pressure is the pressure of the air within the alveoli, which changes during the different phases of breathing (Figure 22.16). Because the alveoli are connected to the atmosphere via the tubing of the airways (similar to the two- and one-liter containers in the example above), the interpulmonary pressure of the alveoli always equalizes with the atmospheric pressure.
|
validation
|
sciq
| null |
What series of reactions is common to fermentation and cellular respiration?
|
[
"metabolism",
"photosynthesis",
"spermatogenesis",
"glycolysis"
] |
D
|
validation
|
sciq
| null |
|
In which ways may sponges reproduce?
|
[
"internally and externally",
"sexually and vertically",
"sexually and asexually",
"meiosis and mitosis"
] |
C
|
The sponge life cycle includes sexual reproduction. Sponges may also reproduce asexually.
|
validation
|
sciq
| null |
What do barnacles anchor to?
|
[
"fossils",
"rocks",
"scales",
"eggs"
] |
B
|
Mo Riza. Barnacles are adapted to the intertidal zone by anchoring to rocks . CC BY 2.0.
|
validation
|
sciq
| null |
Organic compounds produced by what process provide the energy and building material for ecosystems?
|
[
"cyclogenesis",
"nuclear fusion",
"glycolysis",
"photosynthesis"
] |
D
|
validation
|
sciq
| null |
|
As you increase the temperature of a liquid what happens to the solubility of a solute?
|
[
"viscosity increases",
"hydrophilic increases",
"solubility increases",
"turbidity increases"
] |
C
|
Temperature affects the solubility of a solute. However, it affects the solubility of gases differently than the solubility of solids and liquids.
|
validation
|
sciq
| null |
The relative sizes of the atoms show several trends with regard to what visual method of organization?
|
[
"vibrations table",
"oscillations table",
"periodic table",
"chemistry table"
] |
C
|
The relative sizes of the atoms show several trends with regard to the structure of the periodic table. Atoms become larger going down a column and smaller going across a period.
|
validation
|
sciq
| null |
Toward the end of pregnancy, the synthesis of oxytocin receptors in what reproductive organ increases?
|
[
"lungs",
"uterus",
"stomach",
"liver"
] |
B
|
Oxytocin When fetal development is complete, the peptide-derived hormone oxytocin (tocia- = “childbirth”) stimulates uterine contractions and dilation of the cervix. Throughout most of pregnancy, oxytocin hormone receptors are not expressed at high levels in the uterus. Toward the end of pregnancy, the synthesis of oxytocin receptors in the uterus increases, and the smooth.
|
validation
|
sciq
| null |
If an animal eats large pieces of food it is known as a?
|
[
"large consumer",
"bulk feeder",
"bulk producer",
"many feeder"
] |
B
|
validation
|
sciq
| null |
|
What are the two vibrating fields that electromagnetic waves consist of?
|
[
"flammable and magnetic",
"magnetic and mechanical",
"electric and magnetic",
"radioactive and magnetic"
] |
C
|
Electromagnetic waves are waves that consist of vibrating electric and magnetic fields. They transfer energy through matter or across space. The transfer of energy by electromagnetic waves is called electromagnetic radiation.
|
validation
|
sciq
| null |
What is the process by which plants and animals increase in size?
|
[
"birth",
"activity",
"growth",
"reproduction"
] |
C
|
validation
|
sciq
| null |
|
How do endocrine hormones travel throughout the body?
|
[
"in the blood",
"in the lymph",
"in mucus",
"in urea"
] |
A
|
Endocrine hormones travel throughout the body in the blood. However, each endocrine hormone affects only certain cells, called target cells.
|
validation
|
sciq
| null |
The post-anal tail is at the end of the organism opposite what?
|
[
"legs",
"head",
"knees",
"fingers"
] |
B
|
The post-anal tail is at the end of the organism opposite the head. It extends beyond the anus.
|
validation
|
sciq
| null |
What is the term for the moles of solute divided by the kilograms of solvent?
|
[
"molar weight",
"molar solvency",
"molality",
"kilocalorie"
] |
C
|
A final way to express the concentration of a solution is by its molality. The molality ( m ) of a solution is the moles of solute divided by the kilograms of solvent. A solution that contains 1.0 mol of NaCl dissolved into 1.0 kg of water is a “one-molal” solution of sodium chloride. The symbol for molality is a lower-case m written in italics.
|
validation
|
sciq
| null |
Active transport moves substances from an area of lower concentration to an area of?
|
[
"the same concentration",
"higher concentration",
"low concentration",
"flat concentration"
] |
B
|
Active transport requires energy because it moves substances from an area of lower to higher concentration. An example is the sodium-potassium pump. Another form of active transport is vesicle transport, which is needed for very large molecules.
|
validation
|
sciq
| null |
How does the skin eliminates excess water and salts?
|
[
"burn",
"sweat",
"itch",
"peel"
] |
B
|
The skin eliminates excess water and salts in sweat.
|
validation
|
sciq
| null |
Organophosphates typically interfere with nerve signal transmission by inhibiting the enzymes that degrade what?
|
[
"prototype molecules",
"protein molecules",
"transmitter molecules",
"potassium molecules"
] |
C
|
validation
|
sciq
| null |
|
What is the horizontal distance between two waves, measured at a common point (crest to crest or trough to trough), called?
|
[
"wavelength",
"linear",
"absorption",
"frequency"
] |
A
|
Seismic waves are just one type of wave. Sound and light also travel in waves. Every wave has a high point called a crest and a low point called a trough . The height of a wave from the center line to its crest is its amplitude . The horizontal distance between waves from crest to crest (or trough to trough) is its wavelength ( Figure below ).
|
validation
|
sciq
| null |
Steroid hormones, such as cortisol and ecdysteroid, are lipids that contain four fused what?
|
[
"oxide rings",
"acid rings",
"carbon rings",
"nitrogen rings"
] |
C
|
validation
|
sciq
| null |
|
The solubility of gases, liquids, and solids are affected by changes in what?
|
[
"volume",
"friction",
"elevation",
"temperature"
] |
D
|
The solubility of gases, liquids, and solids are affected by changes in temperature.
|
validation
|
sciq
| null |
Only animals have muscle tissue and what other type of tissue?
|
[
"cartilage",
"nervous",
"vascular tissue",
"nonvascular tissue"
] |
B
|
23.29 Characteristics of an Animal • There is no one universally accepted definition of an animal. The following treatment follows your text, beginning on page 876. • Animals: • Are multicellular, heterotrophic eukaryotes . • Lack the distinctive cell walls of plants & fungi • Share unique characteristics . • Share certain reproductive characteristics . • Other commonly used definitions . Animals are multicellular heterotrophic eukaryotes • Unfortunately, none of these traits is exclusive to animals: • Plants, fungi, and some algae are multicellular. • Many bacteria, protists, and all fungi are heterotrophic. • Everything other than bacteria and archaea are eukaryotic. • Moreover, all three of these characteristics also apply to fungi. • However, there is a difference here between animals and fungi. Animals generally take in their food through ingestion, or eating and swallowing something. Fungi are absorptive heterotrophs; they secrete their digestive enzymes onto their food, and then absorb the resulting nutrients. Animals share unique characteristics • Only animals have muscle tissue and nervous tissue. • Only animals have collagen, a structural protein • Only animals have the following types of intercellular junctions: (See pages 135 - 139, Figure 7.15 in your text for more information on these junctions.
|
validation
|
sciq
| null |
What type of matter transmits light but scatters the light as it passes through?
|
[
"a mirror",
"opaque matter",
"translucent matter",
"refractive matter"
] |
C
|
Translucent matter is matter that transmits light but scatters the light as it passes through. Light passes through translucent objects but you cannot see clearly through them because the light is scattered in all directions. The frosted glass panes at the bottom of the window above are translucent.
|
validation
|
sciq
| null |
During an earthquake, the ground shakes as stored up energy is released from what?
|
[
"rocks",
"the soil",
"fossils",
"grass"
] |
A
|
During an earthquake, the ground shakes as stored up energy is released from rocks.
|
validation
|
sciq
| null |
Tunnel vision involves the loss of what visual fields?
|
[
"quickly-moving",
"distant",
"underwater",
"peripheral"
] |
D
|
A unique clinical presentation that relates to this anatomic arrangement is the loss of lateral peripheral vision, known as bilateral hemianopia. This is different from “tunnel vision” because the superior and inferior peripheral fields are not lost. Visual field deficits can be disturbing for a patient, but in this case, the cause is not within the visual system itself. A growth of the pituitary gland presses against the optic chiasm and interferes with signal transmission. However, the axons projecting to the same side of the brain are unaffected. Therefore, the patient loses the outermost areas of their field of vision and cannot see objects to their right and left. Extending from the optic chiasm, the axons of the visual system are referred to as the optic tract instead of the optic nerve. The optic tract has three major targets, two in the diencephalon and one in the midbrain. The connection between the eyes and diencephalon is demonstrated during development, in which the neural tissue of the retina differentiates from that of the diencephalon by the growth of the secondary vesicles. The connections of the retina into the CNS are a holdover from this developmental association. The majority of the connections of the optic tract are to the thalamus—specifically, the lateral geniculate nucleus. Axons from this nucleus then project to the visual cortex of the cerebrum, located in the occipital lobe. Another target of the optic tract is the superior colliculus. In addition, a very small number of RGC axons project from the optic chiasm to the suprachiasmatic nucleus of the hypothalamus. These RGCs are photosensitive, in that they respond to the presence or absence of light. Unlike the photoreceptors, however, these photosensitive RGCs cannot be used to perceive images. By simply responding to the absence or presence of light, these RGCs can send information about day length. The perceived proportion of sunlight to darkness establishes the circadian rhythm of our bodies, allowing certain physiological events to occur at approximately the same time every day.
|
validation
|
sciq
| null |
Systemic mycoses spread to internal organs, most commonly entering the body through this?
|
[
"infestation system",
"respiratory system",
"digestive system",
"skeletal system"
] |
B
|
Systemic mycoses spread to internal organs, most commonly entering the body through the respiratory system. For example, coccidioidomycosis (valley fever) is commonly found in the southwestern United States, where the fungus resides in the dust. Once inhaled, the spores develop in the lungs and cause symptoms similar to those of tuberculosis. Histoplasmosis is caused by the dimorphic fungus Histoplasma capsulatum. It also causes pulmonary infections, and in rarer cases, swelling of the membranes of the brain and spinal cord. Treatment of these and many other fungal diseases requires the use of antifungal medications that have serious side effects. Opportunistic mycoses are fungal infections that are either common in all environments, or part of the normal biota. They mainly affect individuals who have a compromised immune system. Patients in the late stages of AIDS suffer from opportunistic mycoses that can be life threatening. The yeast Candida sp. , a common member of the natural biota, can grow unchecked and infect the vagina or mouth (oral thrush) if the pH of the surrounding environment, the person’s immune defenses, or the normal population of bacteria are altered. Mycetismus can occur when poisonous mushrooms are eaten. It causes a number of human fatalities during mushroompicking season. Many edible fruiting bodies of fungi resemble highly poisonous relatives, and amateur mushroom hunters are cautioned to carefully inspect their harvest and avoid eating mushrooms of doubtful origin. The adage “there are bold mushroom pickers and old mushroom pickers, but are there no old, bold mushroom pickers” is unfortunately true.
|
validation
|
sciq
| null |
The three features that are unique to the large intestine are the teniae coli, haustra, and what?
|
[
"binary appendages",
"disc appendages",
"radial appendages",
"epiploic appendages"
] |
D
|
Anatomy Three features are unique to the large intestine: teniae coli, haustra, and epiploic appendages (Figure 23.23). The teniae coli are three bands of smooth muscle that make up the longitudinal muscle layer of the muscularis of the large intestine, except at its terminal end. Tonic contractions of the teniae coli bunch up the colon into a succession of pouches called haustra (singular = hostrum), which are responsible for the wrinkled appearance of the colon. Attached to the teniae coli are small, fat-filled sacs of visceral peritoneum called epiploic appendages. The purpose of these is unknown. Although the rectum and anal canal have neither teniae coli nor haustra, they do have well-developed layers of muscularis that create the strong contractions needed for defecation.
|
validation
|
sciq
| null |
Most living things build proteins from the same 20 different what?
|
[
"amino acids",
"atomic isolates",
"acid peptides",
"uncommon acids"
] |
A
|
if the salt produced is an acidic salt.
|
validation
|
sciq
| null |
What reaction, along with photosynthesis, provides energy to the vast majority of living things?
|
[
"primarily respiration",
"devices respiration",
"cellular respiration",
"Internal Respiration"
] |
C
|
The chemical reactions of photosynthesis and cellular respiration together provide energy to virtually all living things on Earth.
|
validation
|
sciq
| null |
Some animals increase body fat in winter to stay?
|
[
"cold",
"warm",
"aware",
"thin"
] |
B
|
validation
|
sciq
| null |
|
Coal, oil, and natural gas are examples of what, which forms when organic matter is under pressure for millions of years?
|
[
"complex carbohydrates",
"nuclear fission",
"fossil fuels",
"solar fuels"
] |
C
|
Millions of years ago, there were so many dead plants and animals that they could not completely decompose before they were buried. They were covered over by soil or sand, tar or ice. These dead plants and animals are organic matter made out of cells full of carbon-containing organic compounds (carbohydrates, lipids, proteins and nucleic acids). What happened to all this carbon? When organic matter is under pressure for millions of years, it forms fossil fuels. Fossil fuels are coal, oil, and natural gas.
|
validation
|
sciq
| null |
Protists play critically important ecological roles as producers and, on the other end of food webs, as what?
|
[
"absorbers",
"decomposers",
"probiotics",
"dissolvers"
] |
B
|
Beneficial Protists Protists play critically important ecological roles as producers particularly in the world’s oceans. They are equally important on the other end of food webs as decomposers. Protists as Food Sources Protists are essential sources of nutrition for many other organisms. In some cases, as in plankton, protists are consumed directly. Alternatively, photosynthetic protists serve as producers of nutrition for other organisms by carbon fixation. For instance, photosynthetic dinoflagellates called zooxanthellae pass on most of their energy to the coral polyps that house them (Figure 13.19). In this mutually beneficial relationship, the polyps provide a protective environment and nutrients for the zooxanthellae. The polyps secrete the calcium carbonate that builds coral reefs. Without dinoflagellate symbionts, corals lose algal pigments in a process called coral bleaching, and they eventually die. This explains why reef-building corals do not reside in waters deeper than 20 meters: Not enough light reaches those depths for dinoflagellates to photosynthesize.
|
validation
|
sciq
| null |
Where do physical laws govern energy flow and chemical cycling?
|
[
"ecosystems",
"environments",
"habitats",
"oceans"
] |
A
|
55.1 Physical laws govern energy flow and chemical cycling in ecosystems.
|
validation
|
sciq
| null |
The distribution of thermal speeds depends strongly on temperature. as temperature increases, the speeds are shifted to higher values and the distribution is what?
|
[
"removed",
"decreased",
"broadened",
"improved"
] |
C
|
The distribution of thermal speeds depends strongly on temperature. As temperature increases, the speeds are shifted to higher values and the distribution is broadened.
|
validation
|
sciq
| null |
Carbohydrates, proteins, lipids, and nucleic acids are the four classes of what type of compounds?
|
[
"chromosomal compounds",
"reversible compounds",
"nutrient compounds",
"biochemical compounds"
] |
D
|
Carbohydrates are one of four classes of biochemical compounds. The other three classes are proteins, lipids, and nucleic acids. In addition to cellulose, carbohydrates include sugars and starches. Carbohydrate molecules contain atoms of carbon, hydrogen, and oxygen. Living things use carbohydrates mainly for energy. For more in-depth information on carbohydrates, you may want to watch the videos at these URLs:.
|
validation
|
sciq
| null |
What is the most important factor in soil formation?
|
[
"carbon",
"fertilizer",
"worms",
"climate"
] |
D
|
Climate is the most important factor in soil formation. The climate of a region is the result of its temperature and rainfall. We can identify different climates by the plants that grow there ( Figure below ).
|
validation
|
sciq
| null |
What is the outer layer of cells in a root called?
|
[
"epidermis",
"muscles",
"igneous",
"skeletal"
] |
A
|
The root has an outer layer of cells called the epidermis, which surrounds areas of ground tissue and vascular tissue. The epidermis provides protection and helps in absorption. Root hairs, which are extensions of root epidermal cells, increase the surface area of the root, greatly contributing to the absorption of water and minerals.
|
validation
|
sciq
| null |
What type of feeders are the largest sharks and rays?
|
[
"resting feeders",
"suspension feeders",
"month feeders",
"resulting feeders"
] |
B
|
validation
|
sciq
| null |
|
Chemical digestion couldn't take place without the help of what?
|
[
"melatonin",
"digestive enzymes",
"pigments",
"neurotransmitters"
] |
B
|
Chemical digestion could not take place without the help of digestive enzymes. An enzyme is a protein that speeds up chemical reactions in the body. Digestive enzymes speed up chemical reactions that break down large food molecules into small molecules.
|
validation
|
sciq
| null |
Where would you find three tiny bones called the hammer, anvil, and stirrup?
|
[
"neck",
"tail bone",
"foot",
"middle ear"
] |
D
|
The middle ear contains three tiny bones (ossicles) called the hammer, anvil, and stirrup. If you look at these bones in the Figure above , you might notice that they resemble the objects for which they are named. The three bones transmit vibrations from the eardrum to the inner ear. The arrangement of the three bones allows them to work together as a lever that increases the amplitude of the waves as they pass to the inner ear.
|
validation
|
sciq
| null |
Energy resources can be put into two categories — renewable or?
|
[
"precious",
"nonrenewable",
"reusable",
"synthetic"
] |
B
|
Energy resources can be put into two categories — renewable or non-renewable. Nonrenewable resources are used faster than they can be replaced. Renewable resources can be replaced as quickly as they are used. Renewable resources may also be so abundant that running out is impossible.
|
validation
|
sciq
| null |
Even the age of earth has been estimated on the basis of what?
|
[
"gasses",
"tree rings",
"membranes",
"radioisotopes"
] |
D
|
Radioactive isotopes, or radioisotopes, can be used to estimate the ages of not only of rocks, but also of fossils and artifacts made long ago by human beings. Even the age of Earth has been estimated on the basis of radioisotopes. The general method is called radioactive dating . To understand how radioactive dating works, you need to understand radioisotopes and radioactive decay.
|
validation
|
sciq
| null |
In the primary response to infection, what are secreted first from plasma cells?
|
[
"pathogens",
"platelets",
"antibodies",
"parasites"
] |
C
|
Figure 17.18 In the primary response to infection, antibodies are secreted first from plasma cells. Upon re-exposure to the same pathogen, memory cells differentiate into antibody-secreting plasma cells that output a greater amount of antibody for a longer period of time.
|
validation
|
sciq
| null |
A hookworm is classified as what type of organism?
|
[
"predator",
"bacterium",
"virus",
"parasite"
] |
D
|
Parasites may live either inside or on the surface of their host. An example of a parasite is a hookworm. Hookworms are roundworms that affect the small intestine and lungs of a host organism. They live inside of humans and cause them pain. However, the hookworms must live inside of a host in order to survive. Parasites may even kill the host they live on, but then they also kill their host organism, so this is rare. Parasites are found in animals, plants, and fungi. Hookworms are common in the moist tropic and subtropic regions. There is very little risk of getting a parasite in industrialized nations.
|
validation
|
sciq
| null |
A pigment within plant cells which absorbs light is called?
|
[
"carbonate",
"xylem",
"green",
"chlorophyll"
] |
D
|
chlorophyll - a pigment within plant cells which absorbs light.
|
validation
|
sciq
| null |
Where does slime mold typically live?
|
[
"in the jungle",
"in the soil and in glaciers",
"decaying plant life and in the soil",
"in the sea"
] |
C
|
Slime molds live on decaying plant life and in the soil.
|
validation
|
sciq
| null |
Genital warts is an sti caused by what?
|
[
"human conoil virus",
"human papova virus",
"human papilloma virus",
"human polyoma virus"
] |
C
|
Genital warts is an STI caused by human papilloma virus (HPV), which is pictured in Figure below . This is one of the most common STIs in U. S. teens. Genital warts can’t be cured, but a vaccine can prevent most HPV infections. The vaccine is recommended for boys and girls starting at 11 or 12 years of age. It’s important to prevent HPV infections because they may lead to cancer later in life.
|
validation
|
sciq
| null |
What do ectotherms use to regulate body temperature?
|
[
"Flexible Energy Source",
"combustion energy sources",
"external energy sources",
"result energy sources"
] |
C
|
Ectotherms, sometimes called cold-blooded animals, do not use the energy of metabolism to regulate body temperature. Instead, they depend on external energy sources, such as sunlight. Fish, for example, will seek out water of different temperatures to regulate body temperature. The amount of energy available is directly related to the metabolic rate of the animal. When energy is scarce, ectotherms may also hibernate. The connection between metabolism and body temperature is a reminder that energy and chemical reactions are intimately related. A basic understanding of this relationship is especially important when those chemical reactions occur within our own bodies. Energy is a vital component of the world around us. Nearly every physical and chemical process, including all the chemical reactions discussed in previous chapters, occurs with a simultaneous energy change. In this chapter, we will explore the nature of energy and how energy and chemistry are related.
|
validation
|
sciq
| null |
What event occurred at the close of the precambrian era?
|
[
"natural selection",
"ecosystem succession",
"spontaneous mutation",
"a mass extinction"
] |
D
|
At the close of the Precambrian 544 million years ago, a mass extinction occurred. In a mass extinction , many or even most species abruptly disappear from Earth. There have been five mass extinctions in Earth’s history. Many scientists think we are currently going through a sixth mass extinction.
|
validation
|
sciq
| null |
A balanced equation has an equal number of what on each side?
|
[
"valencies and electrons",
"protons and neutrons",
"electrons and neutrons",
"protons and reactions"
] |
B
|
If you count the number of protons and neutrons on each side of this equation, you’ll see that the numbers are the same on both sides of the arrow. This means that the equation is balanced. The thorium-234 produced in this reaction is unstable, so it will undergo radioactive decay as well. The alpha particle produced in the reaction can pick up two electrons to form the element helium. This is how most of Earth’s helium formed.
|
validation
|
sciq
| null |
Pure substances have a constant composition and can only be changed by what?
|
[
"chemical reactions",
"growth",
"radiation",
"carbon reactions"
] |
A
|
Pure substances have a constant composition and can only be changed by chemical reactions. They can be classified as either elements or compounds.
|
validation
|
sciq
| null |
Earthquakes occur most often at which natural feature?
|
[
"artificial boundaries",
"pattern boundaries",
"plate boundaries",
"plate holes"
] |
C
|
The vast majority of earthquakes happen at plate boundaries.
|
validation
|
sciq
| null |
How many atmospheric circulation cells are there?
|
[
"six",
"two",
"three",
"five"
] |
A
|
The globe has six atmospheric circulation cells. Three are north of the Equator and three are south. These cells have names.
|
validation
|
sciq
| null |
Proper chemical formulas for ionic compounds balance the total positive charge with what?
|
[
"total electric charge",
"total atomic charge",
"total negative charge",
"total ionic charge"
] |
C
|
Proper chemical formulas for ionic compounds balance the total positive charge with the total negative charge.
|
validation
|
sciq
| null |
Which process helps microorganisms make food with chemicals pouring out of deep-sea vents?
|
[
"biosynthesis",
"photosynthesis",
"synaptogenesis",
"chemosynthesis"
] |
D
|
There are many more organisms around deep-sea vents. Microorganisms use chemicals that pour out of the vents to make food by chemosynthesis. These producers support large numbers of other organisms, including crustaceans and red tubeworms like those pictured in Figure below .
|
validation
|
sciq
| null |
What is a combination of two or more substances in any proportion called?
|
[
"combination",
"solvent",
"solution",
"mixture"
] |
D
|
Not all combined substances are compounds. Some are mixtures. A mixture is a combination of two or more substances in any proportion. The substances in a mixture may be elements or compounds. The substances don’t combine chemically to form a new substance, as they do in a compound. Instead, they keep their original properties and just intermix. Examples of mixtures include salt and water in the ocean and gases in the atmosphere. Other examples are pictured in Figure below .
|
validation
|
sciq
| null |
Where is the youngest seafloor located?
|
[
"at the base",
"at the floor",
"at the ridge",
"at the reefs"
] |
C
|
The youngest seafloor is at the ridge. The oldest is farthest from the ridge. The oldest seafloor is much younger than the oldest continent.
|
validation
|
sciq
| null |
What kind of mixture consists of two or more phases, exemplified when a combination of oil and water forms layers?
|
[
"complex miture",
"simple mixture",
"heterogeneous",
"homogeneous"
] |
C
|
A phase is any part of a sample that has a uniform composition and properties. By definition, a pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers. Each of the layers is called a phase.
|
validation
|
sciq
| null |
The values of strangeness assigned to various particles are based on what?
|
[
"atomic mass",
"decay systematics",
"thermal energy",
"penetration potential"
] |
B
|
lifetimes on the order of 10 s (the exception is Σ , whose short lifetime is explained by its particular quark substructure. ), implying that their decay is caused by the weak force alone, although they are hadrons and feel the strong force. The decay modes of these particles also show patterns—in particular, certain decays that should be possible within all the known conservation laws do not occur. Whenever something is possible in physics, it will happen. If something does not happen, it is forbidden by a rule. All this seemed strange to those studying these particles when they were first discovered, so they named a new quantum number strangeness, given the symbol S in the table given above. The values of strangeness assigned to various particles are based on the decay systematics. It is found that strangeness is conserved by the strong force, which.
|
validation
|
sciq
| null |
Together, the muscular and skeletal organs are known as what?
|
[
"cardiovascular system",
"lymphatic system",
"musculoskeletal system",
"nervous system"
] |
C
|
CHAPTER REVIEW 6.1 The Functions of the Skeletal System The major functions of the bones are body support, facilitation of movement, protection of internal organs, storage of minerals and fat, and hematopoiesis. Together, the muscular system and skeletal system are known as the musculoskeletal system.
|
validation
|
sciq
| null |
What do factories and power plants use to remove particulates and waste gases from exhaust before releasing it?
|
[
"scrubbers",
"compressors",
"catalytic converters",
"mufflers"
] |
A
|
Scrubbers are used in factories and power plants. They remove particulates and waste gases from exhaust before it is released to the air. You can see how a scrubber works in Figure below .
|
validation
|
sciq
| null |
Humans typically have how many pairs of chromosomes?
|
[
"14 pairs",
"17 pairs",
"23 pairs",
"25 pairs"
] |
C
|
No, you only received half of your mother's chromosomes and half of your father's chromosomes. If you inherited them all, you would have twice the number of chromosomes that you're supposed to have. Humans typically have 23 pairs of chromosomes. If you received all your parents' chromosomes, you would have 46 pairs!.
|
validation
|
sciq
| null |
Correlation is different from what term that refers to the factor that is producing the effect?
|
[
"causation",
"manifestation",
"correlation",
"differentiation"
] |
A
|
But correlation does not necessarily indicate causation. Causation refers to the factor that is producing the effect. If I push a toy car, I will cause it to move. To explain the difference between correlation and causation, let’s look at an example. Sugar consumption in the United States has been rising for decades ( Figure below ). There is a positive correlation between sugar consumption and rising average global temperatures.
|
validation
|
sciq
| null |
What organelles do animal cells use to convert food into energy?
|
[
"flagellum",
"nucleus",
"endoplasmic reticulum",
"mitochondria"
] |
D
|
When an animal needs energy, it eats food. That's why animals use mitochondria to convert food into energy. Plants, on the other hand, don't seem to eat anything. Instead, they receive energy from water and sunlight. They use chloroplasts to convert light into energy through photosynthesis. The focus of this concept is to delineate the distinct differences between plant and animal cells.
|
validation
|
sciq
| null |
Where does egg production happen?
|
[
"fallopian tube",
"testes",
"uterus",
"ovaries"
] |
D
|
Egg production takes place in the ovaries. It takes several steps to make an egg:.
|
validation
|
sciq
| null |
What can be used to estimate the energy change of a chemical reaction?
|
[
"chemical energy",
"bond magnitudes",
"bond energies",
"isoenergies"
] |
C
|
Bond energies can be used to estimate the energy change of a chemical reaction. When bonds are broken in the reactants, the energy change for this process is endothermic. When bonds are formed in the products, the energy change for this process is exothermic. We combine the positive energy change with the negative energy change to estimate the overall energy change of the reaction. For example, in.
|
validation
|
sciq
| null |
Destructive interference occurs when two identical waves are superimposed exactly out of phase. a standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not do this?
|
[
"substrate",
"membrane",
"propagate",
"reproduce"
] |
C
|
Superposition is the combination of two waves at the same location. Constructive interference occurs when two identical waves are superimposed in phase. Destructive interference occurs when two identical waves are superimposed exactly out of phase. A standing wave is one in which two waves superimpose to produce a wave that varies in amplitude but does not propagate. Nodes are points of no motion in standing waves. An antinode is the location of maximum amplitude of a standing wave. Waves on a string are resonant standing waves with a fundamental frequency and can occur at higher multiples of the fundamental, called overtones or harmonics. Beats occur when waves of similar frequencies f 1 and f 2 are superimposed. The resulting amplitude oscillates with a beat frequency given by.
|
validation
|
sciq
| null |
What is the layer outside the cell wall in a prokaryote?
|
[
"capsule",
"membrane",
"pod",
"rim"
] |
A
|
Many prokaryotes have another layer, called a capsule, outside the cell wall. The capsule protects the cell from chemicals and drying out. It also allows the cell to stick to surfaces and to other cells.
|
validation
|
sciq
| null |
What delivers natural gas from rock that might not otherwise be obtainable?
|
[
"rippling",
"fracking",
"drilling",
"grinding"
] |
B
|
Fracking delivers natural gas from rock that might not otherwise be obtainable.
|
validation
|
sciq
| null |
Name the white blood cells that can squeeze through capillary walls and swallow particles.
|
[
"neutrophils",
"hemoglobin",
"platelets",
"lymphocytes"
] |
A
|
Neutrophils are WBCs that can squeeze through capillary walls and swallow particles such as bacteria and parasites.
|
validation
|
sciq
| null |
Permanent dipole-dipole interactions are found in what kind of molecules?
|
[
"polar",
"directional",
"dual",
"geologic"
] |
A
|
Polar molecules have permanent dipole-dipole interactions.
|
validation
|
sciq
| null |
The energy released during an earthquake is called what?
|
[
"magnitude",
"tidal",
"hydro",
"radiation"
] |
A
|
The ways seismologists measure an earthquake have changed over the decades. Initially, they could only measure what people felt and saw, the intensity. Now they can measure the energy released during the quake, the magnitude.
|
validation
|
sciq
| null |
Many replication forks develop along a what?
|
[
"nucleus",
"genome",
"chromosome",
"allele"
] |
C
|
Many replication forks develop along a chromosome. This process continues until the replication forks meet, and the all of the DNA in a chromosome has been copied. Each new strand that has formed is complementary to the strand used as the template. Each resulting DNA molecule is identical to the original DNA molecule. During prophase of mitosis or prophase I of meiosis, these molecules of DNA condense into a chromosome made of two identical "sister" chromatids. This process ensures that cells that result from cell division have identical sets of genetic material, and that the DNA is an exact copy of the parent cell’s DNA.
|
validation
|
sciq
| null |
What is the term for the strength of an acid or base?
|
[
"carbon",
"pH",
"texture",
"acidity"
] |
D
|
The strength of an acid or base is called acidity. It depends on how much of the substance breaks down into ions when it dissolves in water.
|
validation
|
sciq
| null |
A bog is a type of ____
|
[
"lake",
"plant",
"wetland",
"stream"
] |
C
|
Not all wetlands are alike, as you can see below ( 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.
|
validation
|
sciq
| null |
In projectile motion, the horizontal displacement of an object is called its what?
|
[
"variety",
"width",
"height",
"range"
] |
D
|
In projectile motion, the horizontal displacement of an object is called its range .
|
validation
|
sciq
| null |
An oil drop is stationary when what downward force exactly equals the upward electrical force on the drop?
|
[
"newtonian",
"magnetic",
"gravitational",
"radiation"
] |
C
|
The charge on the plates is adjustable. By measuring the terminal velocity of the oil drops with the electric field off, Millikan could determine the mass of the drops. Millikan and his graduate assistant were able to determine the force of the field on the drops when it was turned on by comparing the velocity of the drops with the field on to their velocity with the field off. This is easily determined when the oil drop is stationary; namely, when the downward gravitational force exactly equals the upward electrical force on the drop.
|
validation
|
sciq
| null |
The secretion of what may influence the body’s circadian rhythms?
|
[
"serotonin",
"melatonin",
"human growth hormone",
"testosterone"
] |
B
|
The secretion of melatonin may influence the body’s circadian rhythms, the dark-light fluctuations that affect not only sleepiness and wakefulness, but also appetite and body temperature. Interestingly, children have higher melatonin levels than adults, which may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty. Finally, an antioxidant role of melatonin is the subject of current research. Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. Some air travelers take melatonin supplements to induce sleep.
|
validation
|
sciq
| null |
Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as this?
|
[
"secondary product",
"primary product",
"reactive product",
"waste product"
] |
D
|
The free electron travels through the electron transport chain, and the energy of the electron is used to pump hydrogen ions into the thylakoid space, transferring the energy into the electrochemical gradient. The energy of the electrochemical gradient is used to power ATP synthase, and the energy is transferred into a bond in the ATP molecule. In addition, energy from another photon can be used to create a high-energy bond in the molecule NADPH. 16 Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.
|
validation
|
sciq
| null |
Purkinje fibers have a fast inherent what?
|
[
"conduction rate",
"replication rate",
"induction rate",
"electromagnetic rate"
] |
A
|
Atrioventricular Bundle (Bundle of His), Bundle Branches, and Purkinje Fibers Arising from the AV node, the atrioventricular bundle, or bundle of His, proceeds through the interventricular septum before dividing into two atrioventricular bundle branches, commonly called the left and right bundle branches. The left bundle branch has two fascicles. The left bundle branch supplies the left ventricle, and the right bundle branch the right ventricle. Since the left ventricle is much larger than the right, the left bundle branch is also considerably larger than the right. Portions of the right bundle branch are found in the moderator band and supply the right papillary muscles. Because of this connection, each papillary muscle receives the impulse at approximately the same time, so they begin to contract simultaneously just prior to the remainder of the myocardial contractile cells of the ventricles. This is believed to allow tension to develop on the chordae tendineae prior to right ventricular contraction. There is no corresponding moderator band on the left. Both bundle branches descend and reach the apex of the heart where they connect with the Purkinje fibers (see Figure 19.19, step 4). This passage takes approximately 25 ms. The Purkinje fibers are additional myocardial conductive fibers that spread the impulse to the myocardial contractile cells in the ventricles. They extend throughout the myocardium from the apex of the heart toward the atrioventricular septum and the base of the heart. The Purkinje fibers have a fast inherent conduction rate, and the electrical impulse reaches all of the ventricular muscle cells in about 75 ms (see Figure 19.19, step 5). Since the electrical stimulus begins at the apex, the contraction also begins at the apex and travels toward the base of the heart, similar to squeezing a tube of toothpaste from the bottom. This allows the blood to be pumped out of the ventricles and into the aorta and pulmonary trunk. The total time elapsed from the initiation of the impulse in the SA node until depolarization of the ventricles is approximately 225 ms.
|
validation
|
sciq
| null |
What process affecting genes or chromosomes causes genetic disorders?
|
[
"graduation",
"radiation",
"mutation",
"infection"
] |
C
|
Many genetic disorders are caused by mutations in one or a few genes. Others are caused by chromosomal mutations. Some human genetic disorders are X-linked or Y-linked, which means the faulty gene is carried on these sex chromosomes. Other genetic disorders are carried on one of the other 22 pairs of chromosomes; these chromosomes are known as autosomes or autosomal (non-sex) chromosomes. Some genetic disorders are due to new mutations, others can be inherited from your parents.
|
validation
|
sciq
| null |
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