Question

Match the greenhouse gases listed in column - II with their respective sources (activities from which they get released) in column - I.
$\begin{array}{cccc}& Column-IActivities& & Column-IIGreenhousegases\\ A& Combustionoffossilfuel& p& Carbondioxide\\ B& Swampandricefields& q& Ozone\\ C& Refrigeration& r& Nitrousoxide\\ D& Burningofbiomass& s& Methane\\ & & t& CF{C}_s\end{array}$

• A. A - s, B - r, C - t, D - q
• B. A - p, B - s, C - t, D - r
• C. A - s, B - r, C - q, D - p
• D. A - r, B - s, C - t, D - p

Answer 1

The correct option is D

A - r, B - s, C - t, D - p

Combustion of fossil fuel causes the release of carbon dioxide. Wetland rice fields are identified as a major source of atmospheric methane. In a natural wetland and in paddy fields, flooding cuts off the oxygen supply from the atmosphere to the soil, which results in anaerobic fermentation of soil organic matter. Methane is a major end product of anaerobic fermentation. It is released from submerged soils to the atmosphere by diffusion and ebullition, through roots and stems of rice plants. Refrigeration requires a refrigerant, that is a substance or mixture, usually a fluid, used in a heat pump and refrigeration cycle. In most cycles it undergoes phase transitions from a liquid to a gas and back again. CFCs are used for this purpose. Burning of biomass primarily releases carbon dioxide, but it also releases another important greenhouse gas, nitrous oxide. Nitrous oxide is released only from the aforementioned process and hence, is matched to the burning of biomass.