Correct Answer - C
Sea water contains 50 times more `CO_(2)` than air . i.e. about 70% of total global carbon is found in oceans. This is in form of carbonates and bicarbonates. The atmosphere is the sources of `CO_(2)` , which is utilised by plants in photosynthesis reduced to form carbon compounds. The total mass of carbon currently in the atmosphere is about `7xx10^(17)g` , i.e. 700000 million tonnes. Oceans regulate the `CO_(2)` content in the atmosphere and thus , play a very important role.
