Fossil fuels are the fuels formed by natural processes such as the decomposition of dead and buried organisms.
Fossil fuels are flammable geologic deposits of organic matter, such as dead plants and animals, that have been buried underneath thousands of feet of silt.
Due to the intense pressure and temperature inside the earth’s crust, these deposits decomposed over time and were changed to natural gas, coal, and petroleum.
They are also regarded as non-renewable energy sources since they require a long time to replenish.