Sources of carbon dioxide in the Earth's atmosphere include decomposition of organic matter (such as trees), the carbon dioxide that animals and people exhale, volcanic activity, and human activities such as the burning of fossil fuels and wood.
(Sources of carbon dioxide in the Earth's atmosphere; include; decomposition of organic matter (such as trees), the carbon dioxide) (the carbon dioxide; animals; )
Sources of carbon dioxide in the Earth's atmosphere the carbon dioxide
include animals
decomposition of organic matter (such as trees), the carbon dioxide