INSIGHT UPSC QUIZ

Science & Technology General Science
Q.

Consider the following statements about Carbon dioxide (CO2):

1. Volcanic eruptions are a natural source of Carbon dioxide in the atmosphere.

2. Carbon dioxide is confined only to the tropospheric layer of the atmosphere. 

3. Excess of Carbon dioxide in the air is removed by green plants by respiration.

Which of the statements given above is/are correct?

Explanation:

ANSWER: (A) 

  • Carbon dioxide: Carbon dioxide (CO2) is released into the atmosphere by respiration, burning of fossil fuels for energy, and by decomposition of limestone during the manufacture of cement. It is also emitted during volcanic eruptions. (Thus, Statement 1 is correct)
  • Carbon dioxide gas is confined to troposphere only. (Thus, Statement 2 is correct)
  • Normally it forms about 0.03 per cent by volume of the atmosphere. With the increased use of fossil fuels, a large amount of carbon dioxide gets released into the atmosphere. Excess of CO2 in the air is removed by green plants and this maintains an appropriate level of CO2 in the atmosphere. 
  • Green plants require CO2 for photosynthesis and they, in turn, emit oxygen, thus maintaining the delicate balance. (Thus, Statement 3 is not correct)
  • As you know, deforestation and burning of fossil fuel increases the CO2 level and disturb the balance in the atmosphere. The increased amount of CO2 in the air is mainly responsible for global warming.

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