The dna of humans and mice is almost 92% similar . this similarity indicates that . nice have a tail , while humans have a tailbone. the tailbone is a structure

Answer

The tailbone is a homologous structure

Explanation

A homologous structure is an organ/bone which is present in different animals (like in humans and the mice) that has common anatomic characteristics which shows that the organisms had a common ancestor. In this case, the organ can relate in functionality or formation.

the answer will be a) proteins i believe

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."