Scientists do not consider vestigial structures in order to determine the closeness between the related organisms.
An anatomical behavior or feature, which no longer appears to possess any purpose in the present form of an organism of the given species.
These vestigial structures were the organs, which performed certain essential functions in the organism at one point of time.
Some of the vestigial structures are sinuses, appendix, external ear, coccyx, nictating membrane, and tonsils.
In order to see closeness between the related organisms, the scientists consider embryonic structures, homologous structures, and analogous structures. However, they do not consider vestigial structures.
Thus, the correct answer is option D, that is, vestigial structures.
Find out more information about vestigial structures here:
https://brainly.com/question/1350219
