Why might a species' "optimal" phenotype remain unchanged for long periods of time, resulting in apparent evolutionary stasis? a. directional selection b. habitat tracking c. gradual environmental change d. saltational evolution e. passive trends

Habitat tracking

Explanation:

The organism change their habitat based on the type of environment they are living in. The climate change so did the habitat and according to that the biota changed.

The number of species are always changing. As the environment change the resident population move to a place where there is a better suited environment for them.

The optimal phenotype in this case does not changes and this common response is called habitat tracking.

i think it is true in my reasonment ..

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."