What is crude oil?
Crude oil is a naturally occurring liquid petroleum product composed of hydrocarbon deposits and other organic materials formed from the remains of animals and plants that lived millions of years ago. These organisms were covered by layers of sand, silt, and rock, subject to heat and pressure, and eventually turned into a type of fossil fuel that is refined into usable products, including gasoline, diesel, liquefied petroleum gases, and feedstock for the petrochemical industry.-
[investopedia.com]