Assume that two species are coexisting in the same environment. species a has little gene pool variation, whereas species b has great variety in its gene pool. during a dramatic environmental change, which event is most probable? a. species a and b will merge into one species. b. species a and b will endure great surges of mutations. c. species a will evolve, whereas species b will have few surviving members. d. species a will become extinct, whereas species b will have surviving members.