Ecologists Are Concerned About Amphibian Populations Because

Ecologists are concerned about amphibian populations because

A) their loss would be an aesthetic loss to the planet.
B) of the possibility of numerous medicinal uses.
C) they are keystone species in many areas-their loss will cause other populations to crash.
D) amphibians are very sensitive to environmental change-they may be indicating serious problems.
E) they are increasing to the point of competing with indigenous species.