Plants can capture only 2-10% of the PAR and this small amount of energy sustains the entire world. Here PAR stands for:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Photosynthetically active radiation
PAR is the part of sunlight that plants can use for photosynthesis. Less than 50 per cent of the sunlight that reaches the earth is PAR. Plants capture only a small part of it.
Option (3) Photosynthetically active radiation — Correct. PAR is photosynthetically active radiation, the part of sunlight that plants can use for photosynthesis. It is less than 50 per cent of the incident solar radiation.
NCERT Extract:
Energy Flow – “Except for the deep sea hydro-thermal ecosystem, sun is the only source of energy for all ecosystems on Earth. Of the incident solar radiation less than 50 per cent of it is photosynthetically active radiation (PAR). We know that plants and photosynthetic bacteria (autotrophs), fix Sun’s radiant energy to make food from simple inorganic materials. Plants capture only 2-10 per cent of the PAR and this small amount of energy sustains the entire living world.”