The correct answer is D. Compressed and hardened biomass.
Coal is a fossil fuel formed from the remains of ancient plants that have been buried and subjected to intense heat and pressure over millions of years. The process of coal formation is called coalification.
Coal is classified into four types: lignite, subbituminous coal, bituminous coal, and anthracite. Lignite is the lowest grade of coal and is the most abundant type of coal. Subbituminous coal is a higher grade of coal than lignite and is used to generate electricity. Bituminous coal is a higher grade of coal than subbituminous coal and is used to generate electricity and make steel. Anthracite is the highest grade of coal and is used to generate electricity and make steel.
Coal is a non-renewable resource and its use contributes to climate change. However, coal is still a major source of energy in many countries.
A. Crude oil is a fossil fuel formed from the remains of ancient marine organisms that have been buried and subjected to intense heat and pressure over millions of years. The process of oil formation is called oil maturation.
B. Deposit of animal waste is not a source of coal. Animal waste is a source of methane, a greenhouse gas.
C. Coke is a solid fuel produced by heating coal in the absence of air. Coke is used in the iron and steel industry.