Question

Global carbon is fixed in the biosphere through photosynthesis.

(a) Explain any two ways by which carbon is returned to the atmosphere through natural processes.

(b) List any two human activities that have influenced the carbon cycle in nature. [3 marks]

Answer 1

(a) Two ways by which carbon is returned to the atmosphere through natural processes are: [1 mark for each point]

i. Through respiratory activities of the producers and consumers, a considerable amount of carbon returns to the atmosphere as CO2.

ii. Decomposers also contribute substantially to CO2 pool by their processing of waste materials and dead organic matter of land or oceans.

(b) Two human activities that have influenced the carbon cycle in nature are: [0.5 mark for each point]

i. Rapid deforestation
ii. Massive burning of fossil fuel for energy and transport