(1) It is the primary source of organic food and food energy (ATP) for all forms of life, either directly or indirectly.

(2) Excess sugars produced in photosynthesis are either stored in the form of carbohydrates or used in the biosynthesis of other organic compounds.

(3) In any ecosystem, green plants represent the most essential biotic components as they are the primary producers.

(4) Photosynthesis helps to purify air and also maintain balance of oxygen and carbon dioxide in the ecosystem.

(5) Oxygenic photosynthesis was responsible for converting the totally anaerobic condition on earth into aerobic atmosphere present now.

(6) The fossil fuels (e.g. natural gas, coal, petroleum (oil), etc.) are all energy-rich materials of an organic origin. The energy stored in all these fuels is basically solar energy which was trapped and stored during photosynthesis in the geological past.

Chapter 5