Biologists Are Studying Two Species Whose DNA Is Known to Differ

Multiple Choice

Biologists are studying two species whose DNA is known to differ by 10%. Which information would be least important in calibrating a molecular clock to determine how rapidly evolution has proceeded with these two species?

A) the fossil record of these two species
B) a geological event that separated the species at a particular time
C) the function of each of these regions of DNA
D) the time of divergence of closely related species