Description : Which of the following is not a commercial source of energy? (1) Coal (2) Petroleum (3) Natural Gas (4) Firewood
Last Answer : (4) Firewood Explanation: Firewood, agricultural waste (straw, etc.) and animals waste (cowdung) are the important components of non-commercial energy. It is generally used in the rural ... . Coal, petroleum products, natural gas and, electricity are the important components of commercial energy.