Final answer:
The liquid fossil fuel formed from ocean organism remains is petroleum. It is created from microscopic marine life subjected to heat and pressure over millions of years and is a major energy source today.
Step-by-step explanation:
The liquid fossil fuel formed from the remains of ocean organisms is petroleum. Petroleum is created from microscopic plants and animals that once lived in ancient seas and were then buried under sediment. Over millions of years, these remains were subjected to heat and pressure, which transformed them into crude oil. Unlike coal, which is a solid fossil fuel, petroleum is a viscous liquid that often migrates and becomes concentrated in reservoirs trapped beneath caprocks. This transformation process took place over hundreds of millions of years, and today, petroleum is extracted and utilized as a critical source of energy.