UPSC CSE Prelims
Question 38
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
- its escape into the outer stratosphere.
- the photosynthesis by phytoplankton in the oceans.
- the trapping of air in the polar ice caps.
Which of the statements given above is/are correct ?
View correct answer and explanation
Correct answer: B
Correct Option: B
Explanation: Ocean phytoplankton absorb CO₂ via photosynthesis, transferring some carbon into organic matter and the ocean system; CO₂ does not escape significantly to space.
Statement / Item-wise Analysis:
1: Incorrect - Incorrect: escape of atmospheric CO₂ to outer space is negligible.
2: Correct - Correct: phytoplankton fix dissolved carbon dioxide during photosynthesis.
3: Incorrect - Incorrect: polar ice does not trap atmospheric air in amounts sufficient to explain the bulk CO₂ sink.
Option-wise Analysis:
A: Incorrect - includes unsupported item 1.
B: Correct - includes the supported statements and excludes the unsupported ones.
C: Incorrect - includes unsupported item 3.
D: Incorrect - includes unsupported item 3; omits supported item 2.