Assertion : Amount of organic matter synthesised by producers per unit time and per unit area during

Question

Assertion : Amount of organic matter synthesised by producers per unit time and per unit area during the process of photosynthesis is referred to as net primary productivity.\ Reason : Primary productivity is usually high and sustained throughout the year in tropical areas due to abundance of sunlight.\

Professor PC Thomas Classes · Answer

(d) : The total amount of organic matter synthesised by producers per unit time and per unit area in the process of photosynthesis is called as gross primary productivity (GPP). Primary productivity is high and sustained throughout the year in tropical areas while it is limited in temperate areas by cold climate and small growing period. Maximum sunlight is available in tropics whereas poles receive minimum sunlight. Due to this, photosynthesis is maximum and net primary productivity (NPP) is highest ( $>20 \mathrm{t} \mathrm{tha}^{-1}$ year $^{-1}$ ) in tropics against average ( $8 \mathrm{t} \mathrm{ha}^{-1}$ year $^{-1}$ ) in temperate forests.