Question

Anatomical features that are fully developed and functional in one group of organisms but reduced and functionless in a similar group are termed vestigial. sympatric. homologous. analogous.

Answer 1

The answer is vestigial.

Step-by-step explanation:

First, the phylogenetic relationship between the two groups must be clear. As long as they're related, it's possible to believe that the lost or diminished structures in the second group are vestigial. This is very common among many species and can be helpful to identify or hypothesize about the phylogenetic history of one species.