Analyse the given scheme and answer the questions.
`{:(" Incident solar radiation"-100%),(" "darr),("Photosynthetically Active Radiation (PAR)"-50%),(" "darr),(" Net primary productivity"-0.8%-4%):}`
a. 50% of solar radiation is available for photosynthesis. Evaluate.
b. Net primary productivity is only `0.8-4%`. Justify.
c. Can you suggest a remedial measure to increase the primary productivity ?

Explanation

a. 50% of solar radiation is reflected back as clouds, absorbed by ozone layer, water vapour and scattered as dust particles.
b. Remaining energy is lost in the form of heat due to respiration.
c. Plant more green plants which increase primary productivity.