Oil source refers to the natural origins of crude oil, which is a vital energy resource used worldwide. Crude oil is formed from the remains of ancient marine organisms, such as plankton and zooplankton, that settled on the ocean floor millions of years ago. Over time, heat and pressure transformed these organic materials into oil, which can be found in underground reservoirs. Countries like Saudi Arabia, Russia, and the United States are known for their significant oil reserves. Extracting oil involves drilling into the earth to access these reservoirs, and the oil is then refined into various products, including gasoline, diesel, and petrochemicals.