What are vestigial traits? what are homologous structures? what are analogous traits? can you explain these using the terms "adaptation" and "common ancestor"?

Vestigial traits are adaptations to environmental pressures which are no longer present.

homologous structures are similar structures found in different species that were present in a common ancestor.

analogous traits are similar traits found in different species that were developed independently (this process is known as convergent evolution)

Interacting group of various species in a common location. for example, a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community.

They use the si unit, or metric system its all the same thing