Net Primary Production Is

Net primary production is

A) heterotrophic production per unit of land per unit of time.
B) energy that photosynthetic organisms make available to other organisms over a given period of time.
C) heterotrophic production minus autotrophic production per unit of land per unit of time.
D) energy made by autotrophs minus energy consumed by heterotrophs, and measured as biomass.
E) energy stored by secondary consumers from primary biomass.