Atmospheric Carbon Serves as A(n)

Atmospheric carbon serves as a(n)

A) exchange pool for carbon that is available to plants for photosynthesis.
B) long-term storage reservoir that becomes available to plants through the action of bacteria.
C) exchange pool for carbon that is made available to plants through the action of bacteria.
D) reservoir of carbon that will eventually be released into the ecosystem through the process of weathering.
E) storage reservoir of carbon that is part of the sedimentary cycle of carbon.