Question

odd one out-natural gas, biomass, wind,sun

Answer 1

natural gas is odd one

Answer 2

Natural gas since other is not the fuel where natural gas is. Biomass, wind and sun are the objects that are present.

Sun and wind are the natural objects that already is present where Biomass is the total volume of the organic waste.

The main similarity between the three is that we can convert them into fuel such as solar energy, wind energy and bio gas whereas we already have natural gas in nature.