Which element can only be converted by bacteria into a form that is available to plants and animals?
a) Carbon
b) Oxygen
c) Nitrogen
d) Hydrogen
Ans: c) Nitrogen
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For a multifactorial, polygenic trait, the characteristic shape of the mathematical plot of frequency for each phenotype class is
A) linear, going up. B) linear, going down. C) a bell curve. D) a square curve.
Sheree is referred to a genetic counselor because a cystic fibrosis (CF) test done as a routine part of her prenatal care indicated that she is a carrier of the most common mutant allele. Sheree is stunned, because no one in her family has the disease. She is 26 years old. The genetic counselor would most likely
A) explain autosomal recessive inheritance and suggest that Sheree's husband be tested for CF. B) explain autosomal dominant inheritance and suggest that Sheree's husband be tested for CF. C) explain autosomal recessive inheritance and suggest that Sheree's parents be tested for CF. D) advise Sheree to have amniocentesis to check the fetus for the CF genotype.
The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?
A. Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy. B. Forelimb evolution was adaptive in people and bats, but not in whales. C. Genes mutate faster in whales than in humans or bats. D. Whales are not properly classified as mammals. E. Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.
Which statement is true about the development of the theory of evolution?
A. Evolution from a common ancestor was proposed 100 years before Darwin's Origin of Species. B. Darwin was the first to propose evolution. C. In Darwin's time most people believed that different organisms evolved from a common ancestor, but they did not know how. D. Initial experiments performed by Darwin did not support his hypothesis.