Petroleum

Petroleum, also known as crude oil, is a naturally occurring, flammable liquid found mainly in underground reservoirs. It is a complex mixture of hydrocarbons of various molecular weights, as well as other organic compounds. Its primary use is as an energy source and it is also used to make many types of fuels, such as gasoline, diesel, jet fuel, and kerosene. Petroleum products are also used to make plastics and many chemical products, such as detergents, fertilizers, and pesticides. Petroleum is of great economic importance, as it accounts for 40% of the world's energy consumption.