Suppose That Mice and Humans Differ by 20 Substitutions in Their

question 121

Multiple Choice

Suppose that mice and humans differ by 20 substitutions in their globin genes, and rats and mice differ by 5 substitutions.On the basis of other evidence, we know that the ancestor to humans and mice lived 80 million years ago.Assuming the molecular clock is operating, rats and mice split from each other _______ million years ago.

• A) 5
• B) 10
• C) 20
• D) 40
• E) 80

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Definitions:

Condyle

A condyle is a round protrusion at the end of a bone that forms part of a joint, allowing movement by articulating with another bone.

Epicondyle

A rounded eminence on a bone, typically found at the end of long bones, near joints, where ligaments and tendons attach.

Fossa

A term for a depression or hollow, often used in anatomy to describe a deep, trench-like structure in bones or tissues.

Medullary Cavity

The central cavity within bones where marrow, which produces blood cells, is stored.