OAT - PRACTICE TEST QUESTION
(NATURAL SCIENCE) EXAM QUESTIONS
WITH CORRECT ANSWERS
One form of colorblindness is caused by gene c carried on the X chromosome in
humans. The gene is recessive to its normal allele C. Far more men are colorblind than
women. Geneticists explain this by pointing out that
A. women possess no X chromosomes in their cells.
B. men carry no genes for color vision on their Y chromosomes.
C. men carry more genes for colorblindness than women do.
D. colorblindness is inhibited by female sex hormones.
E. colorblindness is promoted by male sex hormones. - ANSWER-B. men carry no
genes for color vision on their Y chromosomes.
Several generations of 2 species of paramecia are observed reproducing at the same
rate. It is noted that population A has fewer phenotypes over time than population B.
This most likely would occur if population B
A. has more surviving offspring.
B. has fewer individuals with recessive
alleles.
C. reproduces asexually.
D. reproduces sexually.
E. has individuals with greater fitness. - ANSWER-D. reproduces sexually.
Gastrulation involves the
A. formation of the blastocoel.
B. formation of germ layers.
C. loss of the blastopore.
D. formation of the blastula.
E. final differentiation of the stomach. - ANSWER-B. formation of germ layers.
Of the germ layers comprising the early
human embryo, which one forms most of the central nervous system?
A. Ectoderm
B. Mesoderm
C. Endoderm
, D. Notochord
E. Dermis - ANSWER-A. Ectoderm
Embryonic induction is a process in which
A. embryonic tissues influence adjacent tissues to differentiate.
B. an unfertilized egg is induced to develop.
C. genes are transferred from one developing tissue to another.
D. resting potentials are induced in neurons of embryos.
E. the maternal parent induces expression of recessive genes in embryos. - ANSWER-
A. embryonic tissues influence adjacent tissues to differentiate.
A deciduous forest biome differs from that of the grassland biome in that the forest
biome receives more
A. sunlight.
B. CO2 for photosynthesis.
C. fixed nitrogen from the soil.
D. moisture.
E. ultraviolet light. - ANSWER-D. Moisture
Which of the following pairs of structures have similarity of function?
A. Thyroid gland and sympathetic nervous system
B. Adrenal cortex and sympathetic nervous system
C. Adrenal cortex and parasympathetic nervous system
D. Adrenal medulla and parasympathetic nervous system
E. Adrenal medulla and sympathetic nervous system - ANSWER-E. Adrenal medulla
and sympathetic nervous system
The adrenal medulla secretes hormones that initiate ________? - ANSWER-flight or
fight response
(epinephrine, norepinephrine)
Which situation will most likely to result in genetic drift?
A. Increase in population size
B. Lack of gene mutation
C. Prevention of emigration
D. Random mating
E. Isolation of a small population from a larger one - ANSWER-E. Isolation of a small
population from a larger one
fibrin - ANSWER-protein that forms the basis of a blood clot
homoglobin - ANSWER-carries oxygen, has an iron atom
(NATURAL SCIENCE) EXAM QUESTIONS
WITH CORRECT ANSWERS
One form of colorblindness is caused by gene c carried on the X chromosome in
humans. The gene is recessive to its normal allele C. Far more men are colorblind than
women. Geneticists explain this by pointing out that
A. women possess no X chromosomes in their cells.
B. men carry no genes for color vision on their Y chromosomes.
C. men carry more genes for colorblindness than women do.
D. colorblindness is inhibited by female sex hormones.
E. colorblindness is promoted by male sex hormones. - ANSWER-B. men carry no
genes for color vision on their Y chromosomes.
Several generations of 2 species of paramecia are observed reproducing at the same
rate. It is noted that population A has fewer phenotypes over time than population B.
This most likely would occur if population B
A. has more surviving offspring.
B. has fewer individuals with recessive
alleles.
C. reproduces asexually.
D. reproduces sexually.
E. has individuals with greater fitness. - ANSWER-D. reproduces sexually.
Gastrulation involves the
A. formation of the blastocoel.
B. formation of germ layers.
C. loss of the blastopore.
D. formation of the blastula.
E. final differentiation of the stomach. - ANSWER-B. formation of germ layers.
Of the germ layers comprising the early
human embryo, which one forms most of the central nervous system?
A. Ectoderm
B. Mesoderm
C. Endoderm
, D. Notochord
E. Dermis - ANSWER-A. Ectoderm
Embryonic induction is a process in which
A. embryonic tissues influence adjacent tissues to differentiate.
B. an unfertilized egg is induced to develop.
C. genes are transferred from one developing tissue to another.
D. resting potentials are induced in neurons of embryos.
E. the maternal parent induces expression of recessive genes in embryos. - ANSWER-
A. embryonic tissues influence adjacent tissues to differentiate.
A deciduous forest biome differs from that of the grassland biome in that the forest
biome receives more
A. sunlight.
B. CO2 for photosynthesis.
C. fixed nitrogen from the soil.
D. moisture.
E. ultraviolet light. - ANSWER-D. Moisture
Which of the following pairs of structures have similarity of function?
A. Thyroid gland and sympathetic nervous system
B. Adrenal cortex and sympathetic nervous system
C. Adrenal cortex and parasympathetic nervous system
D. Adrenal medulla and parasympathetic nervous system
E. Adrenal medulla and sympathetic nervous system - ANSWER-E. Adrenal medulla
and sympathetic nervous system
The adrenal medulla secretes hormones that initiate ________? - ANSWER-flight or
fight response
(epinephrine, norepinephrine)
Which situation will most likely to result in genetic drift?
A. Increase in population size
B. Lack of gene mutation
C. Prevention of emigration
D. Random mating
E. Isolation of a small population from a larger one - ANSWER-E. Isolation of a small
population from a larger one
fibrin - ANSWER-protein that forms the basis of a blood clot
homoglobin - ANSWER-carries oxygen, has an iron atom
