Why do fossil fuels like natural gas and crude oil have higher energy densities than peat?

Peat is an early stage of fossil-fuel formation and contains more water and less concentrated carbon-rich material. Over long periods, burial pressure and heat transform organic matter into fuels such as natural gas and crude oil, which store more energy per unit of mass. Therefore, “formed under greater pressure and heat, concentrating their stored energy” is the best choice.

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