What Characteristics Would Determine Whether Structures from Two Kinds of Organisms

Question

What characteristics would determine whether structures from two kinds of organisms are homologous?
A) The structures should have identical functions in both organisms.
B) The structures should be in different positions on the bodies of the two organisms.
C) The structures should not appear in any close relatives of the organisms.
D) The structures should have similar anatomy in the two organisms.

Accepted Answer

Homologous structures are similar in anatomy, although they may have different functions in different organisms. Therefore, the structures in two kinds of organisms should have similar anatomy for them to be considered homologous. The other options, such as identical functions or different positions on the bodies, do not necessarily indicate homology. The structures may have evolved independently in each organism or may be analogous rather than homologous.