SSC CGL 2021 PYQ — Question 46

The correct answer is option 1 i.e. Methane

• Methane is the primary gas that is known as "marsh gas".
• Anaerobic digestion, like pyrolysis, occurs in the absence of air; but in this case the decomposition is caused by bacterial action rather than high temperatures.
• Anaerobic digestion takes place naturally in decaying vegetation on the bottom of ponds, producing the marsh gas which bubbles to the surface and can even catch fire. 
• Global wetlands are one of the largest sources of atmospheric methane. That's where the name marsh comes from because it is the gas produced from marshy lands.