Populations of mosquitofish have diverged from each other in environments that are different, based on the presence/absence of a predator. Is this an example of allopatry or sympatry?

This is an example of sympatry.      

Explanation:

Sympatry: Refers to two similar species that coincide in part or their whole distribution area. There are two ways in which two species can reach sympatry.

Allopatry: Refers to the case in which two species are completely separated from each other, with no overlapping. This separation is due to the emergence of a barrier that separated the original species, and after that, the two populations evolved separately in different new species.

In the exposed example there is no barrier, but the presence/absence of a predator might be acting as an environmental pressure of the populations´ microhabitats that leads to divergence.

the darker peppered moth species were favored due to the fact that the industrial revolution had made all the nearby trees a darker color instead of white.

the cell cycle is the final answer! : )