The equation for the formation of glucose is 6CO2+6H2O=C6H12O6+6O2. Glucose is a carbohydrate that provides energy to many organisms. Photosynthesis is the process that produces glucose.
Plants and some species of algae use photosynthesis to convert energy from light, carbon dioxide and water into glucose and oxygen. Photosynthesis is the process that provides the world with breathable oxygen.
The organisms that use glucose as an energy source can do so through aerobic respiration, anaerobic respiration or fermentation. Humans primarily use aerobic respiration to convert glucose into energy. One of the byproducts of aerobic respiration is carbon dioxide: a compound that plants must have to perform photosynthesis.