Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of 1. Its escape into the outer stratosphere. 2. the photosynthesis by phytopl

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Q: 21 (IAS/2011)
Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of
1. Its escape into the outer stratosphere.
2. the photosynthesis by phytoplankton in the oceans.
3. the trapping of air in the polar ice caps.
Which of the statements given above is/ are correct ?

question_subject: 

Ecology

question_exam: 

IAS

stats: 

0,117,420,115,117,245,60

keywords: 

{'carbon dioxide': [2, 0, 5, 6], 'photosynthesis': [20, 0, 4, 11], 'lower atmosphere': [0, 0, 0, 2], 'atmosphere': [1, 1, 4, 7], 'polar ice caps': [0, 0, 1, 2], 'outer stratosphere': [0, 0, 0, 1], 'oceans': [8, 1, 8, 19], 'phytoplankton': [1, 0, 0, 1], 'air': [1, 0, 0, 0], 'trapping': [1, 0, 0, 1], 'concentration': [0, 0, 4, 7], 'human activities': [0, 0, 0, 3]}

Out of the three statements given:

  1. Carbon dioxide (CO2) molecules can indeed escape into the outer stratosphere, but this is not a significant process in removing CO2 from the lower atmosphere. In the stratosphere, CO2 can actually absorb more radiation and contribute to further warming of the atmosphere. So, statement 1 is incorrect.

  2. Photosynthesis by phytoplankton in the oceans is a process that can remove carbon dioxide from the atmosphere. During photosynthesis, phytoplankton use CO2 to create organic matter, which eventually settles at the bottom of the ocean and sequesters the carbon. Therefore, statement 2 is correct.

  3. Trapping of air in the polar ice caps can preserve the composition of the atmosphere from past periods, but it is not a process that removes CO2 from the current atmosphere. Therefore, statement 3 is incorrect.

Hence, the correct answer is option (b) 2 only.

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