A biologist reads an article in a scientific journal that describes how the legs of different organisms look and function differently, but appear to be

constructed from the same basic bones. He compares a drawing of the

skeletal structure of a porpoise's fin with one of an elephant's leg. (7A)

What aspect of the theory of evolution do these drawings support?

Homology

Explanation:

The aspect of the theory of evolution that the drawings support is homology. Homologous organs are organs of different organisms that look similar in structure but perform different functions in reality.

Organs that are built on the same or similar basic plans in the same organisms but perform different functions are thought to have been from the same ancestor. Hence, homology or homologous organ represents one of the evidence used to support the theory of evolution which opines that all living organisms descended with modifications from common ancestors.

the answer to your question is:

c. complementary base-pairing