Explanation

Vestigial structures are often called vestigial organs, although many of them are not actually organs. Such vestigial structures typically are degenerated atrophied or rudimentary and tend to be much more variable than homologous non-vestigial parts. Although structures commonly regarded ‘vestigial’ may have lost some or all of the functional roles that they had played in ancestral organisms, such structures may retain lesser functions or may have become adapted to the new roles in an extant population