The structural similarities between the flippers of whales and the arms of humans are used to show that the:
A. Whales evolved from the human species.
B. Human species began life in the oceans.
C. Whales are older than the human species.
D. Human species and whales have a common ancestry.
Comparing structural similarities is called comparative anatomy. The more similar two different species body structures are, the closer the evolutionary link, and the more recently they shared a common ancestor.