The carbon cycle doesn’t start or end but, where I am going to start explaining it is in the air. The carbon or CO2 gets absorbed into the green plants like trees. The animals and plants respire and but the carbon back into the air. Then the trees and animals die and become decaying matter and gives off Carbon and goes into the ground to make fossil fuels. The Fossil fuels then power the factories. The factories then use combustion to but the carbon back into the air to star the cycle over again.