Keystone species:

A) are always symbionts.
B) are typically not the most abundant species in the community.
C) illustrate secondary succession.
D) always form the base of a food chain.
E) are only found in tropical communities.

Keystone Species

A species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically.

Symbionts

The partners in a symbiotic relationship.

Secondary Succession

Secondary succession is the ecological process of change and development in an area where an ecosystem has been previously established but has then been disrupted.