Question

what is the primary source of petroleum?
decayed animal matter
inorganic compounds
wind energy
sunlight

Explanation:

Petroleum is formed from the remains of ancient marine organisms (such as plankton and algae) which are organic in nature. Over millions of years, these decayed organic matters (not inorganic compounds, wind energy, or sunlight) under high - pressure and temperature conditions transform into petroleum.

Answer:

decayed animal matter