In death valley, california, there are several ponds that are formed in various areas of the desert. each pond contains its own species of fish unique to the pond it lives in.
a. geographic isolation
b. anatomical isolation
c. behavioral isolation
d. temporal isolation

A. Geographical Isolation

Explanation - Geographical Isolation alludes to the physical obstructions that exist that shield two species from mating. For instance, a types of monkey that is situated on an island can't breed with another types of monkey on the terrain.

The water separates the two species by keeping them secluded from each other and make it unthinkable for them to breed. In this case, fishes of different ponds cannot breed because they are separated from one pond to another.  

the index of refraction of the second medium is higher. i just took the test trust me !