Which of the following is a heterogeneous mixture of decomposed plant material that is accumulated in water, in the absence of air?
Coal is formed when organic material is buried under sediment and exposed to high temperature and pressure for millions of years.
The formation of coal takes place in four stages: peat→ lignite→ bituminous →anthracite coal.
Peat is a heterogeneous mixture of more or less decomposed plant material that is accumulated in water, in the absence of air (anaerobic conditions). Peat is the primitive form of coal. The carbon content of peat is least when compared to lignite, bituminous, or anthracite coal.