Carbon is one of the most abundant elements in the universe and can be found in many places.

- The atmosphere contains carbon dioxide (CO2) composed of one carbon atom and two oxygen atoms.

- The oceans contain dissolved carbon in the form of bicarbonate ions (HCO3-) and carbonate ions (CO32-).

- Carbon is also found in fossil fuels such as coal, oil, and natural gas, and organic matter in living organisms and soil.

- Inorganic carbon is found in the Earth's crust in the form of minerals like limestone (CaCO3), dolomite (CaMg(CO3)2, and graphite (pure carbon).