A Population of Mountain Goats Are Split Because of the Formation

Multiple Choice

A population of mountain goats are split because of the formation of a glacier.After 500 years the glacier melts and the two goat populations are free to move between the two areas.Under what conditions might the populations be able to occasionally interbreed?

A) Both pre- and post-zygotic isolating mechanisms have arisen.
B) Reproductive isolation is incomplete.
C) Pre-zygotic isolating mechanisms have arisen.
D) Post-zygotic isolating mechanisms have arisen.
E) Gene flow between the two populations does not occur.