Assertion : Methane component of green house gases contributing to global warming is about 20 percent.…

Assertion : Methane component of green house gases contributing to global warming is about 20 percent. Reason : Introduction of multi-point fuel injection engines in automobiles has decreased methane content in the exhausts.
  1. both assertion and reason are true and reason is the correct explanation of assertion
  2. both assertion and reason are true but reason is not the correct explanation of assertion
  3. assertion is true but reason is false
  4. both assertion and reason are false.

Solution

Methane is largely a product of incomplete decomposition and is produced by a group of bacteria called methanogens under anaerobic conditions. The major sources of methane include freshwater wetlands, enteric fermentation in cattle and flooded rice fields. Biomass burning also produces methane. Major gases contributing in greenhouse effect with their percentage contribution are given in the given pie chart. Efficient engine (for example, multi point fuel injection engine) can reduce the unburnt carbons (like methane etc.) in auto emission.

Asked in: NEET 2008 (Mains)

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