Q. What is the carbon cycle?

The carbon cycle represents the recycling and circulation of the chemical element carbon in nature as a result of the action of living beings.

The Photosynthetic beings absorb carbon as carbon dioxide available in the atmosphere and the carbon atoms become part of glucose molecules. Throughout the cellular respiration of these beings part of this organic material is consumed to generate ATP and in this process carbon dioxide is returned to the atmosphere and the other part is incorporated by the photosynthetic organisms into the molecules that compose their structure. The carbon atoms included into the producers are transferred to the next trophic level and again part is liberated by the cellular respiration of the consumers, part becomes a constituent of the consumer body and the part is excreted as urea or uric acid (excretes later recycled by decomposer bacteria). Thus carbon absorbed by the producers in photosynthesis returns to the atmosphere throughout cellular respiration along the food chain until the decomposers that also liberate carbon dioxide in their energetic metabolism. Under the special conditions in a process that takes millions of years carbon incorporated into organisms may also constitute fossil fuels stored in deposits under the surface of the planet as fossil fuels burn the carbon atoms return to the atmosphere as carbon monoxide or carbon dioxide. The burning of vegetable fuels like as wood that as well returns carbon to the atmosphere.