Petroleum is a natural, liquid fossil fuel composed mainly of hydrocarbons, formed from the remains of ancient marine organisms buried under layers of sediment for millions of years. It is extracted from the earth through drilling and is refined into various products, including gasoline, diesel, jet fuel, and lubricants. Petroleum is a crucial energy source globally, powering transportation, heating, and electricity generation, but its extraction and use also contribute to environmental concerns, such as pollution and climate change.