The carbon cycle is an important gaseous cycle which has its reservoir pool in the

atmosphere. All living organisms contain carbon as a major body constituent.

Carbon is a fundamental element found in all living forms. All biomolecules such

as carbohydrates, lipids, and proteins required for life processes are made of

carbon. Carbon is incorporated into living forms through a fundamental process

called ‘photosynthesis’. Photosynthesis uses sunlight and atmospheric carbon

dioxide to produce a carbon compound called ‘glucose’. This glucose molecule

is utilized by other living organisms. Thus, atmospheric carbon is incorporated in

living forms. Now, it is necessary to recycle this absorbed carbon dioxide back

into the atmosphere to complete the cycle. There are various processes by which

carbon is recycled back into the atmosphere in the form of carbon dioxide gas.

The process of respiration breaks down glucose molecules to produce carbon

dioxide gas. The process of decomposition also releases carbon dioxide from dead

bodies of plants and animals into the atmosphere. Combustion of fuels,

industrialization, deforestation, volcanic eruptions, and forest fires act as other

major sources of carbon dioxide.