DENDROLOGY

Detailed explanation-1: -During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose.

Detailed explanation-2: -The carbon atoms used to build carbohydrate molecules comes from carbon dioxide, the gas that animals exhale with each breath. The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules.

Detailed explanation-3: -Carbon dioxide (CO2) comes from both natural sources (including volcanoes, the breath of animals and plant decay) and human sources (primarily the burning of fossils fuels like coal, oil and natural gas to generate energy).

Detailed explanation-4: -Carbon is released back into the atmosphere when organisms die, volcanoes erupt, fires blaze, fossil fuels are burned, and through a variety of other mechanisms.