Explanation:

All of the above are correct.Methane (CH,) is one of the trace gases in the atmosphere that is considered to play a
major role in what is called the "greenhouse effect".
There are six major sources of atmospheric methane: emission from anaerobic decomposition
in (1) natural wetlands and (2) paddy rice fields; (3) emission from livestock
production systems (including intrinsic fermentation and animal waste); (4) biomass
burning (including forest fires, charcoal combustion, and firewood burning); (5) anaerobic
decomposition of organic waste in landfills, and (6) fossil methane emission during the
exploration and transport of fossil fuels. Obviously, human activities play a major role in
increasing methane emissions from most of these sources. Especially the worldwide
expansion of paddy rice cultivation, livestock production and fossil fuel exploration have
increased the methane concentration in the atmosphere.