Question

Despite their differences in appearance, all bony fish have common ancestors. Their fins develop from similar structures and usually have a prescribed number of bones. Because of this, the large rudder-like dorsal fin of a sailfish, the poisonous dorsal fin of a catfish, and the tiny reduced dorsal fin of a puffer fish are said to be ________ structures.
Responses
A vestigialvestigial
B analagousanalagous
C homologoushomologous
D evolutionary

Answer 1

C — homologous.

These fins share a common ancestral origin and similar developmental/structural patterns (even if shape and function differ), so they are homologous structures.