Of the total incident solar radiation the proportion of PAR is

Correct Option (c) Reason : The source of energy in all ecosystem is solar energy. About 50% of the solar energy incident over earth is present in PAR (Photosynthetically active Radiation). About 1-5% of incident solar radiation or 2-10% of PAR is captured by the photosynthetic organisms in the synthesis of organic matter (gross primary productivity).

Roughly 20% of it is consumed in respiration so that net capture of energy (net primary productivity) is 0.8-4% of incident radiation or 1.6-8% of PAR.