Question

what is: an organ that no longer functions in an organism and which is homologous to a functioning organ in another organism

Answer 1

Vestigial structures

Step-by-step explanation:

Vestigial structures are anatomical structures of organisms in a species which are considered to have lost much or all of their original function through evolution. ... Vestigial structures are often referred to as vestigial organs, though not all of them are actually organs.

Answer 2

I think the answer is Vestigial structures