Q23 / 180 · AIIMS 2006 · Botany

Assertion : The concentration of methane in the atmosphere has more than doubled in the last 250 years. Reason : Wetlands and rice fields are the major sources of methane.

  • Correct answer
    A
    If both assertion and reason are true and reason is the correct explanation of the assertion
  • B
    If both assertion and reason are true but reason is not the correct explanation of the assertion
  • C
    If assertion is true, but reason is false
  • D
    Both assertion and reason are false statements.

Solution

Hydrocarbon are major air pollutants. Methane is produced naturally during decomposition of organic matter, incomplete biomass combustion. Its concentration was $700 \mathrm{ppb}$ in pre industrial times and $1750 \mathrm{ppb}$ in 2000 . So the concentration has more than doubled in the last 250 years. Flooded paddy fields, marshes, cattles etc. are the major sources of this gas.

Hence, the correct answer is option: 'A'.

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