Answer:
C. Net Primary productivity
Step-by-step explanation:
In an the food chain of an ecosystem, energy is constantly being gained and most. Producers are the set of organisms that start the energy cycle via the process of photosynthesis. The gross primary productivity (GPP) is the amount of energy that the producer is able to capture from sunlight during photosynthesis.
The rate at which that captured energy is used to produce chemical organic compounds, which served as food, is called the primary productivity of the producer. However, the NET PRIMARY PRODUCTIVITY (NPP) is the energy available to consumers, which is determined by subtracting the energy used by plants via metabolism, from the total energy transformed by the process of photosynthesis. Hence, mathematically, NPP = GPP - R
Where, R = energy lost via respiration.