Florida Biology EOC Practice Test 2025 – 400 Free Practice Questions to Pass the Exam

The correct terminology for a structure in an organism that no longer serves its original function is "vestigial structures." Vestigial structures are remnants of evolutionary history; they may have served a purpose in the organism's ancestors but have lost or altered their original function over time. A well-known example of this is the human appendix, which is thought to have once had a significant role in digesting cellulose from plant material but now has no essential function in most humans.

Analogous structures refer to features in different species that serve similar functions but do not share a common ancestry. Homologous structures, on the other hand, are features that are similar due to shared ancestry, although they may serve different functions in modern species. Primitive structures is not a defined term in the context of evolution and biology regarding structures that have lost function.

Each of these terms relates to the study of evolutionary biology and comparative anatomy, but vestigial structures specifically identify those components that have lost their original significance.