a self regulating feedback system.
Reason: The reservoir pool of carbon consists of free `CO_(2)` in the atmosphere.

Answer

C

Explanation

Biogeochemical cycle of carbon is a gaseous cycle. Its cycling pool consists of `6xx10^(14) kg(29%)` of free `CO_(2)` in the oceans. Oceans also regulate the amount of `CO_(2)` in the atmosphere. Reservoir pool of carbon is lithosphere. Lithosphere contains `2.8xx10^(21)` kg of carbon. Natural exchange between lithosphere and hydroshpere or atmosphere is a very slow process. Major exhange in carbon cycle occurs between organisms and the atmosphere or hydrophere. This cycling is a self-regulated feedback system but has recently been upset due to rapid deforestation and increasing combustion of fossil fuels.