EVERYDAY SCIENCE

Detailed explanation-1: -Photosynthesis is the process of synthesis of food by plants using carbon dioxide and water in presence of sunlight and chlorophyll. Oxygen (O2) is released during the process as a waste product. Hence, oxygen is not essential for the process of photosynthesis.

Detailed explanation-2: -Oxygen is mainly released as a by-product by photolysis of water and released in the atmosphere. Thus, it is not required for photosynthesis.

Detailed explanation-3: -None of the anoxygenic phototrophic bacteria have the ability to use water as an electron donor (or cannot oxidize water), and, thus, perform photosynthesis using sulfide, hydrogen or organic substrates. Therefore, photosynthesis by these bacteria does not involve oxygen.

Detailed explanation-4: -The correct option is A True. During photosynthesis, Carbon dioxide(CO2) gas is taken in through stomata from the atmosphere. Oxygen(O2) gas is released through stomata into the atmosphere as a by-product.