Homologous structures are structures found in one species that have the same basic anatomical structure and embryonic origin as those found in another species. If homologous structures are found on organisms of two different species, the species are related, even if only distantly. Which of the following structures are homologous and illustrate evidence of an evolutionary relationship? A.a bird's wing and a butterfly's wing
B. a catfish's fin and a bee's antenna C.a whale's flipper and a cat's leg D.a wasp's wing and a dolphin's flipper

By homology is meant similarity between structures of different organisms, due solely to the same embryological origin. The homologous structures may or may not perform the same function.

Man's arm, cat's leg, bat's wing, and whale's fin are all homologous structures, since they all have the same embryological origin.

In such cases, there is no functional similarity. However, when analyzing the bat wing and the bird wing, it appears that both have the same embryological origin and are still associated with the same function.

The homology between structures of 2 different organisms suggests that they originated from a common ancestral group, although it does not indicate a common degree of proximity, departing from several evolutionary lines that originated several different species, we speak of adapted irradiation.