<P> Carbon sources include: </P> <Ul> <Li> Combustion of fossil fuels (coal, natural gas, and oil) by humans for energy and transportation </Li> <Li> Farmland (by animal respiration); there are proposals for improvements in farming practices to reverse this . </Li> </Ul> <Li> Combustion of fossil fuels (coal, natural gas, and oil) by humans for energy and transportation </Li> <Li> Farmland (by animal respiration); there are proposals for improvements in farming practices to reverse this . </Li>

Where are the natural stores of carbon found