Which Statement Is True with Regard to Keystone Species

Multiple Choice

Which statement is true with regard to keystone species?

A) Animals can be keystone species, but plants cannot.
B) Top predators can be keystone species, but other animals cannot.
C) Insects can never be keystone species because they are pests.
D) Some keystone species are more vulnerable to extinction than other species.
E) A species must have a very large population size in order to be a keystone species.