Question

why the process of photosynthesis is necessary

Answer 1

The oxygen released (with water vapor, in transpiration) as aphotosynthetic byproduct, principally of phytoplankton, provides most of the atmospheric oxygen vital to respiration in plants and animals, and animals in turn produce carbon dioxide necessary to plants.

Answer 2

Plants are the only living thing which produces food during photosynthesis.Photosynthesis is necessary because other animals who do not produce food, feed on plants to get energy. It is the basis of all the food chains. It also plays a very important role in converting carbon dioxide (CO2) into oxygen (O2) so that both the humans and animals can breathe.