AP BIOLOGY

Detailed explanation-1: -During combustion or burning, carbon from fossil fuels combine with oxygen in the air to form carbon dioxide and water vapor. These natural hydrocarbon fuels come from once-living organisms and are made from carbon and hydrogen, which release carbon dioxide and water when they burn.

Detailed explanation-2: -Respiration, excretion, and decomposition release the carbon back into the atmosphere or soil, continuing the cycle.

Detailed explanation-3: -During complete combustion carbon and hydrogen combine with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). During incomplete combustion part of the carbon is not completely oxidized producing soot or carbon monoxide (CO).

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.