Petroleum is formed due to _____________.

Petroleum is a fossil fuel that is formed from the remains of dead animals and plants. When the animals and plants die, they sink down and settle on the sea bed of the oceans. Millions of years ago, the dead vegetation and wildlife got decomposed and then got mixed with the silt and sand.

Then certain bacteria helped in decomposing this organic matter with which some chemical changes were caused, which led to the formation of petroleum.

Hence, Petroleum is formed due to the decomposition of organic matter.