A complication of molecular clock studies is that
A) DNA and proteins appeared in life at about the same time.
B) genes mutate at different rates.
C) DNA is not often preserved in fossils.
D) some species are more highly evolved than others.
B) genes mutate at different rates.
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The production of chlorophyll molecules requires most plants to obtain __________ from the
soil.
a. calcium b. magnesium c. nitrogen d. potassium
Many gastropods have external shells composed of:
a. two valves. b. eight overlapping valves. c. a series of internal chambers. d. one valve. e. chitin.
Consider two IgG molecules, each of which reacts with a different epitope. Which of the following
statement(s) is(are) TRUE?
a. They will have the same amino acid sequence in their constant regions. b. They will have different amino acid sequences in their variable regions. c. They can bind the same antigen. d. They can bind different antigens. e. They can bind the same antibody.
In reproductive cloning, cells are subjected to an electric current under special circumstances. What effect does this have?
A) It mimics fertilization and begins embryonic development. B) It removes an udder cell from an adult. C) It introduces recombinant DNA. D) It removes DNA from an egg.