Which of the following facts implies that humans and fish had a common ancestor? a. both species are consumers. b. both species have the ability to swim. c. both species must expel waste materials. d. both species have gill slits when they are embryos.

an adaptation is a change or process by which an organism takes to be better suited for its environment. for example; migration is a behavioral adaptation, this is needed because birds are not built to last extremely cold climates. there are different adaptations because there are different species needing to adjust to different things, bears don't migrate; they hibernate.