Natural Sciences 1
My persnal Study tests coppied for questions on the Natural Sciences study guide to CLEP Natural Sciences.
- 1.
Bony fishes are members of the class
- A.
Chondrichthyes
- B.
Osteichthyes
- C.
Agnatha
- D.
Amphibia
- E.
Aves
Correct Answer
B. OsteichthyesExplanation
Oste- in the class name Osteichthyes means "bone." Chondrichthyes are the cartilaginous fish, Agnatha, the jawless fish.Rate this question:
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- 2.
A classic experiment on the origin of life was performed in 1953. It showed that organic molecules could have resulted from the interaction of gases and lightning in the atmosphere of early Earth. This is known as the ______________ experiment.
- A.
Miller-Urey
- B.
Milgram
- C.
Meselson and Stahl
- D.
Hershey-Chase blender
- E.
Oparin
Correct Answer
A. Miller-UreyExplanation
The Miller-Urey experiment used simulated lightning and a mixture of compounds that were presumed to have existed on Earth before life came about. Organic compounds were produced, supporting the hypothesis that such compounds could arise independent of organisms.Rate this question:
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- 3.
Which of the following is NOT recognized as one of the five kingdoms of life?
- A.
Monera or Prokaryotae
- B.
Plantae
- C.
Chordata
- D.
Fungi
- E.
Protista or Protoctista
Correct Answer
C. ChordataExplanation
Chordata is a phylum in kingdom Animalia.Rate this question:
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- 4.
In the scientific name for the house mouse, Mus musculus, Mus is the _________ while, musculus is the _________.
- A.
Order, class
- B.
Species, subspecies
- C.
Species, genus
- D.
Genus, species
- E.
Class, genus
Correct Answer
D. Genus, speciesExplanation
The first letter of the genus name is always capitalized, as in Mus. The species name is written in lowercase (e.g., musculus). Both are printed in italics or underlined in handwritten manuscripts.Rate this question:
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- 5.
Cladogenesis means
- A.
A species evolves into another, totally different species.
- B.
A species evolves into another, totally different species, and the parent species ceases to exist.
- C.
An evolutionary line of descent splits, branching into two or more lines.
- D.
A new species arises due to physical isolation, such as on an island.
- E.
The gene pool of population changes due to the founder effect.
Correct Answer
C. An evolutionary line of descent splits, branching into two or more lines.Explanation
Cladogenesis may also be involved in a similar evolutionary process called adaptive radiation. Choice B. describes the other form speciation may take, anagenesis. Choice D. defines allopatric speciation.Rate this question:
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- 6.
The oldest fossils are about
- A.
50 million years old
- B.
550 million years old.
- C.
1 billion years old.
- D.
3 billion years old.
- E.
6 billion years old.
Correct Answer
D. 3 billion years old.Explanation
Earth is about 5 billion years old, and the first signs of life are bacteria-like fossils that are 3 billion years old.Rate this question:
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- 7.
Oxygen is NOT required for which one of the following processes?
- A.
Glycolysis
- B.
Kreb's cycle
- C.
Electron transport system
- D.
Citric acid cycle
- E.
All of the above.
Correct Answer
A. GlycolysisExplanation
Glycolysis is an anaerobic process that does not require free oxygen. "Kreb's cycle" and "citric acid cycle" are synonyms.Rate this question:
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- 8.
In humans, oogenesis results in the production of
- A.
Four ova.
- B.
Two ova
- C.
One ovum and three polar bodies
- D.
One ovum and one polar body.
- E.
Two ova and two polar bodies.
Correct Answer
C. One ovum and three polar bodiesExplanation
Meiosis I results in one cell and one polar body. The second round of meiosis (Meiosis II) involves a division of this cell, and produces the ovum and two more polar bodies.Rate this question:
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- 9.
Which of the following is found in both prokaryotic and eukaryotic cells?
- A.
Ribosomes
- B.
Mitochondria
- C.
Chloroplasts
- D.
Membrane-bound nucleus
- E.
Nucleoid region
Correct Answer
A. RibosomesExplanation
Choices B., C., and D. are features of the eukaryotic cell, while a nucleoid region is associated with Prokaryotes.Rate this question:
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- 10.
A plant that grows on another plant but derives only physical support and not nutritional sustenance from that plant (e.g., Spanish moss, lichen, and moss on tree trunks) is termed an
- A.
Epistat
- B.
Episome
- C.
Epiphyte
- D.
Epiphysis
- E.
Epitope
Correct Answer
C. EpiphyteExplanation
The incorrect terms come from other areas of biology as diverse as molecular biology (episome), immunology (epitope), or anatomy (epiphysis). It is imperative to make use of important clues, such as that one answer ends in -phyte, which refers to plants.Rate this question:
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- 11.
In theory, what is the net number of ATP molecules that can be derived from one molecule of glucose after it has been processed through glycolysis, the Kreb's cycle, and the electron transport system?
- A.
30
- B.
32
- C.
34
- D.
36
- E.
38
Correct Answer
D. 36Explanation
While a total of 38 ATP molecules is produced, the net yield is only 36 ATP, since at the start of glycolysis 2 ATP molecules are used to phosphorylate the glucose molecule (often called "priming the pump"). Note that this yield of ATP is theoretical—actual net yields are not this high.Rate this question:
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- 12.
RNA is found in what form(s) in the cell?
- A.
MRNA
- B.
TRNA
- C.
RRNA
- D.
A, B, and C
- E.
A and B
Correct Answer
D. A, B, and CExplanation
mRNA (messenger RNA) is a transcript of the DNA being expressed. tRNA (transfer RNA) is a cloverleaf-shaped molecule that has an amino acid on one end and an anticodon, specific to that amino acid, on the other end. rRNA (ribosomal RNA) is part of the ribosome.Rate this question:
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- 13.
Humans as a species first appeared during which geologic era?
- A.
Cenozoic
- B.
Paleozoic
- C.
Precambrian
- D.
Mesozoic
- E.
Silurian
Correct Answer
A. CenozoicExplanation
All other answers are also geologic eras, except Silurian, which is a period in the Mesozoic era.Rate this question:
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- 14.
The Hershey-Chase (blender) experiments were based on the fact that
- A.
Phosphorus is found in viral nucleic acids, while sulfur is found in viral proteins.
- B.
Phosphorus is found in viral proteins, while sulfur is found in viral nucleic acids.
- C.
Sulfur is found in both viral proteins and viral nucleic acids.
- D.
Phosphorus is found in both viral proteins and viral nucleic acids.
- E.
Sulfur and phosphorus are both found in viral nucleic acids and viral proteins.
Correct Answer
A. Phosphorus is found in viral nucleic acids, while sulfur is found in viral proteins.Explanation
No phosphorus is found in proteins, and no sulfur is found in nucleic acids. Hershey and Chase employed these facts by using a radioactive isotope of sulfur to label the protein in the viral coat of bacteriophage, while a radioisotope of phosphorus was used to label the viral nucleic acid enclosed within the protein coat. This let them clearly distinguish the protein from the DNA.Rate this question:
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- 15.
The primary producers in a food pyramid consist of
- A.
Herbivores
- B.
Carnivores
- C.
Heterotrophs
- D.
Photosynthetic autotrophs
- E.
Bacteria
Correct Answer
D. Photosynthetic autotrophsExplanation
Photosynthetic autotrophs provide the entry point for solar energy, which can then be shuffled among members of a food chain going from level to level.Rate this question:
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- 16.
A relationship in which one organism benefits from another (a host), but in which the host is not injured, is an example of
- A.
Mutualism
- B.
Commensalism
- C.
Batesian mimicry.
- D.
Parasitism
- E.
Infection
Correct Answer
B. CommensalismExplanation
In parasitism, the host is harmed; in mutualism, both organisms benefit from the interaction.Rate this question:
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- 17.
The modern system of naming organisms as genus and species is known as __________________, and was developed by the biologist Linnaeus.
- A.
Binomial numerology
- B.
Cladistics
- C.
Great Chain of Being
- D.
Taxons
- E.
Binomial nomenclature
Correct Answer
E. Binomial nomenclatureExplanation
Modern taxonomy, of which binomial nomenclature is an important part, uses Latin or Latinized words, since Latin is a dead and, therefore, fixed language. Each organism has a two-part name, as in Homo sapiens. Higher groupings (such as class or order) lump related organisms together.Rate this question:
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- 18.
The third stage, or step, in mitosis is
- A.
Telophase
- B.
Metaphase
- C.
Cytokinesis
- D.
Anaphase
- E.
Prophase
Correct Answer
D. AnaphaseExplanation
Mitosis progresses from prophase to metaphase, to anaphase, and finally to telophase. Cytokinesis refers to the actual splitting of one cell into two distinct daughter cells, following the nuclear division of mitosis. Not all cells that undergo mitosis follow with cytokinesis. For instance, muscle cells are frequently multinucleate.Rate this question:
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- 19.
In which one of the following biomes are most resources concentrated above the ground?
- A.
Temperate grassland
- B.
Tundra
- C.
Tropical rain forest
- D.
Desert
- E.
Deciduous forest
Correct Answer
C. Tropical rain forestExplanation
Tropical rain forests have nutrients and other resources concentrated in the vegetation and animals, and the small amount of nutrients found in the soil are located shallowly, in the first few inches of soil.Rate this question:
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- 20.
The light reactions of photosynthesis occur
- A.
On the thylakoid membranes
- B.
Within the matrix
- C.
In the cytosol
- D.
On the membrane forming the cristae
- E.
On the rough endoplasmic reticulum
Correct Answer
A. On the thylakoid membranesExplanation
Thylakoid membrane is found within chloroplasts. The complex molecules that carry out the reactions of the light-dependent phase of phtotosynthesis are located there. The matrix and cristae are features of mitochondria.Rate this question:
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- 21.
The dance of the bees, the means by which a honeybee communicates information about the location of a food resource to the hive, was discovered and first described by
- A.
August Weismann
- B.
Francisco Redi.
- C.
Julian Huxley
- D.
Karl von Frisch
- E.
Knut Schmidt-Nielsen
Correct Answer
D. Karl von FrischExplanation
Of the biologists listed, only von Frisch and, to a lesser degree, Huxley, were involved in studies of animal behavior.Rate this question:
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- 22.
Estuaries are
- A.
Saltwater marshlands characterized by water of high salinity.
- B.
Areas of ocean where saltwater and freshwater meet and mix, resulting in water with an intermediate and changing salinity.
- C.
Areas in which sea birds and their nests are protected by federal law.
- D.
Parts of land that are alternately covered and uncovered by saltwater as the tides change each day.
- E.
Any area of ocean in which the salinity is above normal.
Correct Answer
B. Areas of ocean where saltwater and freshwater meet and mix, resulting in water with an intermediate and changing salinity.Explanation
An estuary forms, for instance, where a river empties into the ocean, and dilutes the ocean water with freshwater.Rate this question:
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- 23.
Which vessels have valves: arteries, veins, or lymph vessels?
- A.
Arteries
- B.
Arteries and lymph vessels
- C.
Veins and lymph vessels
- D.
Arteries and veins
- E.
Veins
Correct Answer
C. Veins and lymph vesselsExplanation
Blood moves through arteries due to fluid pressure generated by the heart and muscles in the arterial walls. Veins and lymph vessels are at much lower pressure, and much of the movement of fluids through such vessels is due to the working of skeletal muscle, rather than blood pressure. Valves materially assist in this action by preventing backflow.Rate this question:
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- 24.
The largest reservoir of carbon on Earth is
- A.
Carbon in the soil.
- B.
Carbon in the oceans
- C.
Carbon in the atmosphere.
- D.
Carbon in plant biomass.
- E.
Carbon in coal.
Correct Answer
B. Carbon in the oceansExplanation
Some carbon in the oceans exists as compounds that act as a pH buffer; much of it is also found in insoluble deposits. The other reservoirs (or sinks) listed also hold considerable amounts of carbon.Rate this question:
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- 25.
The basic functional unit of the mammalian kidney is the
- A.
Neuron
- B.
Nephrite
- C.
Nephron
- D.
Neurolemma
- E.
None of the above
Correct Answer
C. NephronExplanation
The kidney consists of many nephrons. Each nephron has these features: a glomerulus, Bowman's capsule, the loop of Henle, the collecting duct, and several convoluted tubules that lead to and from the loop of Henle. There are more than 1 million nephrons in each human kidney.Rate this question:
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- 26.
DNA is found in which cell organelles?
- A.
Mitochondria
- B.
Ribosomes
- C.
Chloroplasts
- D.
A, B, and C
- E.
A and C
Correct Answer
E. A and CExplanation
Both organelles possess their own DNA. Ribosomes contain ribosomal RNA (rRNA), but not DNA.Rate this question:
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- 27.
Maltose is composed of
- A.
Two molecules of fructose bonded together.
- B.
Two molecules of glucose bonded together.
- C.
One molecule of glucose bonded to one molecule of fructose.
- D.
One molecule of lactose bonded with one molecule of glucose.
- E.
One molecule of galactose bonded to one molecule of glucose.
Correct Answer
B. Two molecules of glucose bonded together.Explanation
Glucose, galactose, and fructose are monosaccharides, while maltose and lactose are disaccharides. Choice C. is the disaccharide sucrose. Choice E. is the disaccharide lactose.Rate this question:
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- 28.
Organisms that can fix atmospheric nitrogen are limited to the kingdom
- A.
Plantae
- B.
Fungi
- C.
Protista (Protoctista).
- D.
Prokaryotae (Monera).
- E.
Animalia
Correct Answer
D. Prokaryotae (Monera).Explanation
Only certain bacteria or blue-green algae (monerans known as cyanobacteria) can remove nitrogen gas from the atmosphere. Nitrogen is converted to ammonia (NH₃) or nitrate (NO₃-).Rate this question:
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- 29.
In humans and other mammals, uric acid is the waste product derived from purines in _________, whereas urea is made from the nitrogen found in ________________.
- A.
Proteins, amino acids
- B.
Nucleic acids, proteins
- C.
Nucleic acids, nucleic acids
- D.
Carbohydrates, proteins
- E.
Nucleic acids, lipids
Correct Answer
B. Nucleic acids, proteinsExplanation
Both urea and uric acid are nitrogenous wastes, but they come from the catabolism (breakdown) of different nitrogen-containing compounds. An important clue here is the word purine, a nitrogenous base that occurs in nucleic acids.Rate this question:
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- 30.
Impulses that stimulate the heart to contract are sent out from the _____ node, located in the right atrium.
- A.
SA
- B.
AV
- C.
ASA
- D.
Purkinje
- E.
Bundle of His
Correct Answer
A. SAExplanation
Purkinje fibers and the Bundle of His are part of the cardiac conduction system that carries the impulses originating in the SA (sinoatrial) node.Rate this question:
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- 31.
The kidney may be divided into two anatomical parts: an outer part, or _____________ (which comes from the Latin word for bark); and an inner part, known as (the) ______________.
- A.
Lateral, medial
- B.
Medulla, cortex
- C.
Cortex, medulla
- D.
Superficial, deep
- E.
Capsule, cortex
Correct Answer
C. Cortex, medullaExplanation
Cortex and medulla are used as names for the parts of several organs, such as the adrenal medulla and cerebral cortex.Rate this question:
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- 32.
The surfaces of plant leaves, and many stems, have openings through which gases are exchanged and transpiration occurs. The openings are known as
- A.
Stomata
- B.
Cuticles
- C.
Palisade cells
- D.
Guard cells
- E.
Mesophyll
Correct Answer
A. StomataExplanation
Stomata (singular form is stoma) are openings in the epidermis of the plant through which gases or water vapor may pass. Two guard cells arranged around the stoma act as doors and regulate the size of the opening, controlling the loss of water vapor and exchange of gases by opening or closing the pore.Rate this question:
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- 33.
Which of the following is NOT an example of a factor limiting population growth that is density-dependent?
- A.
Infectious disease
- B.
Predation
- C.
Competition for food
- D.
Floods
- E.
Parasitism
Correct Answer
D. FloodsExplanation
Of the five factors listed, all but flooding will kill a greater proportion of individuals if population density is high (e.g., higher population density increases the chances of passing infections among individuals).Rate this question:
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- 34.
Which of the following statements best defines a population?
- A.
Individuals of a single species that occupy a particular locale at a particular time; often the individuals interbreed and are isolated from other populations
- B.
All individuals of a particular species that are alive at the same time
- C.
A population consists of two or more interbreeding subpopulations and occupy contiguous territories
- D.
A group of organisms and the organisms they feed on in one geographical area
- E.
A population is any species under study that is found in a habitat characterized by a particular type of vegetation in or entering a specific stage of succession
Correct Answer
A. Individuals of a single species that occupy a particular locale at a particular time; often the individuals interbreed and are isolated from other populationsExplanation
Basically, a population is composed of the individuals of one species occupying a specific area.Rate this question:
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- 35.
Two hormones that help regulate the functioning of the kidneys are ________________ and ______________.
- A.
Testosterone, ADH
- B.
Aldosterone, LDH
- C.
Aldosterone, ADH
- D.
Aldosterone, AHD
- E.
ADH, estrogen
Correct Answer
C. Aldosterone, ADHExplanation
Aldosterone and ADH (anti-diuretic hormone) are key hormones in the regulation of the kidneys. Testosterone and estrogen are sex hormones.Rate this question:
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- 36.
In mammals, all blood cells and platelets are produced in the
- A.
Thymus
- B.
Spleen
- C.
Bone marrow
- D.
Liver
- E.
None of the above
Correct Answer
C. Bone marrowExplanation
All cellular elements of the blood—white cells and red cells—are made in the bone marrow from a single type of parent cell, called the stem cell. Platelets are not cellular but are derived from the breakup of a larger cell also produced in the bone marrow.Rate this question:
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- 37.
In seed plants, the tissue that envelops and supplies nutrients to the embryo is called the
- A.
Fruit
- B.
Endocarp
- C.
Pericarp
- D.
Endosperm
- E.
Ovule
Correct Answer
D. EndospermExplanation
Do not confuse endosperm with fruit, which is a ripened ovary enclosing the seeds.Rate this question:
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- 38.
Deuterostomes may be distinguished from protostomes in that
- A.
Deuterostome zygotes undergo spiral cleavage, while protostomes go through radial cleavage.
- B.
The blastopore of deuterostomes becomes the anus of the developed organism, while in protostomes the blastopore forms a mouth.
- C.
Only deuterostomes are also coelomates.
- D.
Only protostomes show radial symmetry in the adult organism.
- E.
All protostomes are extinct.
Correct Answer
B. The blastopore of deuterostomes becomes the anus of the developed organism, while in protostomes the blastopore forms a mouth.Explanation
This is a fundamental difference between the two groups and the basis for the naming them. The deutero- part of the name refers to two, meaning the two openings (mouth and anus) of the adult organism.Rate this question:
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- 39.
A cross is performed between a tall garden pea plant known to be heterozygous for tallness (Tt), and another tall pea plant of undetermined genotype. Which of the following statements lists all the potential F1 phenotypes that could result from this cross?
- A.
All tall
- B.
Ratio of 1:2:1 for TT : Tt : tt
- C.
All tall or 3:1 tall:short
- D.
:1 tall:short or 2:1 tall:short
- E.
3:1 tall:short
Correct Answer
C. All tall or 3:1 tall:shortExplanation
It is impossible to specify one particular outcome, as the genotype of the second plant is unknown—it might be TT or Tt. Note that choice B., which might seem to be another possible correct answer, lists a genotype and genotypic ratio. The question asks for phenotypes or phenotypic ratios.Rate this question:
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- 40.
In the embryo, mesoderm gives rise to
- A.
Muscle, bone, and circulatory system.
- B.
Nerve tissue.
- C.
Digestive system and liver.
- D.
Hair and nails.
- E.
Skin
Correct Answer
A. Muscle, bone, and circulatory system.Explanation
Choices B., D., and E. are derived from ectoderm, while choice C. comes from endoderm.Rate this question:
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- 41.
___________ give(s) rise to secondary growth in plants.
- A.
Apical meristems
- B.
Ground meristem
- C.
Procambium
- D.
Lateral meristems
- E.
Protoderm
Correct Answer
D. Lateral meristemsExplanation
Meristems are areas of active cell division in plants, and they give rise to permanent tissue. Apical meristem occurs in stem and root tips. Ground meristem is the source of pith and cork. Protoderm is a meristem that produces epidermis. Procambium gives rise to vascular tissue (xylem and phloem). Lateral meristem is found in roots and stems surrounding phloem.Rate this question:
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- 42.
The antibodies transferred to a nursing infant in its mother's milk are an example of
- A.
Activated immunity.
- B.
A toxoid
- C.
An antigen
- D.
Passive immunity
- E.
Active immunity
Correct Answer
D. Passive immunityExplanation
Passive immunity results from the transfer of antibodies and is therefore temporary. The protection they confer lasts only as long as the antibodies persist in the recipient's body. Active immunity results from the stimulation of the animal's immune system by an antigen, which results in production of the organisms own antibodies. A toxoid is a toxin (such as that produced by the tetanus bacillus) that has been treated to render it innocuous, while retaining its activity as an antigen.Rate this question:
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- 43.
Approximately how much energy is passed from one trophic level to another when going up a food chain?
- A.
1 percent
- B.
10 percent
- C.
35 percent
- D.
65 percent
- E.
90 percent
Correct Answer
B. 10 percentExplanation
Only about 10 percent of the energy of one trophic level is passed on to the next. The great loss of energy progressively reduces the biomass that can be supported at each trophic level.Rate this question:
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- 44.
In most mammals, including humans,
- A.
Females have two X chromosomes, and males have one X and one Y chromosome.
- B.
Females have X and Y chromosomes, and males have two X chromosomes.
- C.
Females have two X chromosomes, both derived from their mother.
- D.
Females have one X chromosome, and males two X chromosomes.
- E.
Females can have either XX or YY chromosomes, while males have X and Y chromosomes.
Correct Answer
A. Females have two X chromosomes, and males have one X and one Y chromosome.Explanation
Other animals such as birds have different sex-chromosome arrangements, but in mammals, XX denotes a female and XY a male.Rate this question:
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- 45.
Which of the following hormones is NOT produced by the anterior pituitary gland?
- A.
Thyroid-stimulating hormone
- B.
Thyroxine
- C.
Prolactin
- D.
Melanocyte-stimulating hormone
- E.
Growth hormone
Correct Answer
B. ThyroxineExplanation
Thyroxine is produced in the thyroid gland. Thyroxine stimulates the breakdown of fats and carbohydrates and is involved in promoting growth. In amphibians, it is needed for metamorphosis to occur.Rate this question:
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- 46.
A swim bladder is found only in
- A.
Chondrichthyes
- B.
Osteichthyes
- C.
Agnatha
- D.
Amphibia
- E.
A and B
Correct Answer
B. OsteichthyesExplanation
Only bony fishes (Osteichthyes) have swim bladders. Cartilaginous fish, such as sharks and rays, and jawless fish (lampreys), do not have swim bladders.Rate this question:
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- 47.
The circulation of the blood was first explained by
- A.
William Harvey.
- B.
Charles Darwin.
- C.
Louis Pasteur.
- D.
Claude Bernard
- E.
Harvey Williams
Correct Answer
A. William Harvey.Explanation
The seventeenth-century discovery of the circulation of the blood by English physician William Harvey was a milestone in the history of biology and medicine.Rate this question:
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- 48.
Which statement is incorrect?
- A.
A haploid cell with 14 chromosomes undergoes mitosis, yielding 2 cells, each with 14 chromosomes.
- B.
A diploid cell with 28 chromosomes undergoes mitosis, producing cells that each bear 14 chromosomes.
- C.
A diploid cell with 28 chromosomes undergoes mitosis, producing cells that each bear 28 chromosomes.
- D.
A diploid cell with 28 chromosomes undergoes meiosis, producing cells that each bear 14 chromosomes.
- E.
A diploid cell with 14 chromosomes undergoes meiosis, producing cells that each bear 7 chromosomes.
Correct Answer
B. A diploid cell with 28 chromosomes undergoes mitosis, producing cells that each bear 14 chromosomes.Explanation
Cells that are produced by mitosis retain the same number of chromosomes found in the parent cell. This rule applies whether the parent cell is haploid (1N) or diploid (2N). Cells resulting from meiosis have half the number (1N) of chromosomes found in the parent cell (which was a diploid cell with a complement of 2N chromosomes). Haploid cells do not undergo meiosis for obvious reasons.Rate this question:
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- 49.
Body systems work together in an integrated fashion to keep the internal environment stable and compatible with life, a process that is called
- A.
Homeothermy
- B.
Homeostasis
- C.
Catabolism
- D.
Buffering
- E.
Isostasis
Correct Answer
B. HomeostasisExplanation
Homeostasis is a concept that is central to any understanding of physiology. Homeothermy is a superficially similar word, but as the -thermy ending suggests, it refers to body temperature—in this instance, the active maintenance of a steady body temperature.Rate this question:
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- 50.
The basic unit of organization in organisms is
- A.
The mitochondrion.
- B.
The membrane-bound nucleus.
- C.
The cell.
- D.
The organ.
- E.
Tissues assembled into organs and organ systems.
Correct Answer
C. The cell.Explanation
This is a fundamental tenet of biology, part of the cell theory first propounded in the 1830s and 1840s. The other part of this theory is: all cells come from preexisting cells.Rate this question:
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