Which organisms have four-chambered hearts?
a. amphibians and most reptiles
b. fish
c. arthropods
d. birds and mammals
e. earthworms
d
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A protein that regulates transcription by binding to the operator is known as the
A. operon. B. repressor. C. promoter. D. operator. E. CAP.
A twitch is contraction and relaxation of
A. one neuron. B. one muscle cell. C. an entire muscle. D. one sarcomere. E. several muscles.
Scientists study animal models in order to reveal the functions of human genes. This is an example of:
a. comparative genomics. b. DNA cloning. c. Western blotting. d. RNAi e. gene targeting.
What is the function of topoisomerase?
A) relieving strain in the DNA ahead of the replication fork B) elongating new DNA at a replication fork by adding nucleotides to the existing chain C) unwinding of the double helix D) stabilizing single-stranded DNA at the replication fork