Question

the major force(s) causing the genetic divergence of the two isolated fruit fly populations is/are
mutation
natural selection and the variety of other species with which each population interbreeds
the complete lack of sexual reproduction in the two populations
mating and gene flow between the two populations
mutation and natural selection

Explanation:

Mutation creates new genetic variations. Natural - selection acts on these variations. In isolated populations, mutation and natural - selection drive genetic divergence as there is no gene - flow to homogenize the gene pools. Interbreeding with other species is not relevant here as the populations are isolated. Lack of sexual reproduction is incorrect as fruit - flies reproduce sexually. Mating and gene - flow between the two populations would decrease divergence, not cause it.

Answer:

E. mutation and natural selection