The largest demand of energy is generally fulfilled by

Explanation

Fuels that are generated very deep under the earth from the debris of plants and animals, which existed millions of years ago, are called fossil fuels. Coal, oil and natural gases are fossil fuels. Fossil fuel energy sources, such as coal, natural gas, and oil are used to meet energy demands for much of the world. Fossil fuel accounts for 84% of world's primary consumption while hydroelectric power accounts for 6%, renewables for 5%, and nuclear power for 4%.