BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Oxygen (O2) production by photosynthesis is by far the dominant global process that replenishes atmospheric and oceanic oxygen essential to sustain all aerobic life.

Detailed explanation-2: -So how did Earth end up with an atmosphere made up of roughly 21 percent of the stuff? The answer is tiny organisms known as cyanobacteria, or blue-green algae. These microbes conduct photosynthesis: using sunshine, water and carbon dioxide to produce carbohydrates and, yes, oxygen.

Detailed explanation-3: -Plants use photosynthesis to capture carbon dioxide and then release half of it into the atmosphere through respiration. Plants also release oxygen into the atmosphere through photosynthesis.

Detailed explanation-4: -Plants consume carbon dioxide-a significant greenhouse gas-in the process of photosynthesis. The reduction of carbon dioxide in the atmosphere has an indirect cooling effect. Plants also cool the atmosphere because they release water vapor when they get hot, a process similar to sweating.