Which ecosystem has the highest average net primary productivity? 

A)  agricultural land 
B)  swamps and marshes 
C)  open ocean 
D)  temperate forest

Net Primary Productivity

The rate at which plants in an ecosystem produce net useful energy (biomass) after accounting for the energy consumed through the process of respiration.

Ecosystem

A biological community of interacting organisms and their physical environment, considered a system through which nutrients are cycled and energy flows.

Average

A statistical measure representing the central or typical value in a set of data, commonly calculated by dividing the sum of all values by the number of values.