2. Exercises II

 

CementStoneTarBitumen is the petroleum product used for surfacing of roads.

 

 

Millions of years ago, trees, plants, ferns, and forests were buried below the rocks, soil, and sand due to naturalphysicalchemicalcombustion processes like flooding, earthquake, etc. Slowly, as more soil was deposited over them, they were compressed. This led to the conditions of pressure and heattemperature and heattemperature and volumepressure and temperature. These conditions, along with the anaerobic conditions, turned the carbon-enriched organic matter of wood into coal. This slow process of conversion of wood into coal is called combustioncarbonisationcoalificationdecomposition.