Answer;
-fossils fuels, burned
Explanation;
Besides plants and animals, wood and fossil fuels can be burned to release carbon into the air.
-There are both natural and human sources of carbon dioxide emissions. Natural sources include decomposition of organisms, ocean release and respiration from both plants and animals.
-Human sources come from activities like cement production, deforestation as well as the burning of fossil fuels like coal, oil and natural gas, and also clearing of forests for agriculture, which releases carbon dioxide through increased biomass decay.
