Comparing which characteristic provides the best information to determine if two different organisms share a common ancestor? A. the differences in their body sizes
B. the similarities between their anatomical structures
C. the adaptations both organisms have made to an environmental change
D. the distance between the locations where both organisms live

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.

the answer is b. glad to .