Physical barriers that prevent (or reduce) the transfer of gametes include
a. ) all of the answers are correct b.) mating isolation - potential mates come into contact but do not mate (behavioral in animals, mediated by specialized pollinators in plant)
c.) allopatric isolation - populations that inhabit ranges that are allopatric d.) ecological isolation - populations that breed at different times (temporal, like Rhagoletis), or in different places (habitat isolation, like Sticklebacks)