Work Step by Step
Option a. is incorrect. A vestigial structure is one that used to have a specific function in an ancestor organism but now no longer has a function. Option c. is incorrect. Speciation is the development of a totally different species through evolutionary means. Option d. is incorrect. Analogous structures are similar structures that develop separately in two different species. Option b. is correct. An adaptation is a trait that is passed down from an ancestor to its descendants that increase an organism's fitness or the ability to survive and reproduce.