Why do scientists consider vestigial structures (like a human appendix) evidence for evolution?

vestigial structures are considered evidence because scientists believe they are structures that were once used by a species ancestors but are not longer needed. these structures do not impair the organism in any way, so there is no need for evolution to get rid of them. for example, the human appendix is considered a vestigial structure.

Explanation:

:D

the wires in the toaster turning red and the toast crisping and turning brown