Structures as Different as Human Arms, Bat Wings, and Dolphin

Multiple Choice

Structures as different as human arms, bat wings, and dolphin flippers contain many of the same bones, these bones having developed from very similar embryonic tissues. How do biologists interpret these similarities?

A) By identifying the bones as being homologous
B) By the principle of convergent evolution
C) By proposing that humans, bats, and dolphins share a common ancestor
D) A and C only
E) A, B, and C