Question

Which of the following processes provides most of the oxygen found in the earth's atmosphere?

• A. Photosynthesis
• B. Fermentation
• C. Excretion
• D. Aerobic respiration

Answer 1

Answer: (A)

Photosynthesis provides most of the oxygen found in the earth's atmosphere. During the light reaction of the photosynthesis, water molecules split in the presence of light and releases protons, electrons and oxygen molecules. This process of splitting of water molecules is known as photolysis.

So, the correct answer is option A.