The lava released by a volcanic eruption separates two populations of a species of monkey. What does this represent?
biological isolation
geographical isolation
temporal isolation
anatomical isolation

That represents geographical isolation.
Biological isolation is present where members of species are not able to produce fertile offspring due to the genetic incompatibility.
Temporal isolation includes differences in the seasons of mating. One species mates in season x and another in season y, means they will not be able to interbreed.
Anatomical isolation means there are differences in the physical structures of the species members that inhabit their ability to mate.