Petroleum originates from organic compounds of both plants and animals, small size or the dead pond and mingle with deposit sediment. Type in an appropriate environment.
Petroleum compounds originating from both plants and small animals or plankton to die and mixed with sediment deposition. Type in the right environment.
Petroleum originated from organic compounds of both plants and animals, small or plankton who died and deposition associated with sediment. Various kind in the right environment.