Ecosystems — BIOLOGY STD 12 Science — Question

Primary productivity is the amount of energy or biomass accumulation in green plants per unit area per unit time. It depends upon the availability of solar radiations, optimum temperature, soil moisture and biogenetic nutrients.
Gross primary productivity is the total organic matter synthesized by the producers in the process of photosynthesis.
Net primary productivity is the total organic matter stored by producers per unit area per unit time.
Secondary productivity is synthesis of organic matter by consumers per unit area per unit time.