How is the formation of crude oil different from the formation of coal?

• A. Crude oil forms into a liquid under extreme pressure while coal forms a solid.
• B. Crude oil forms from rapid evaporation of seawater.
• C. Coal forms from geothermal heat into a gas.
• D. Oil and coal form in the same way.

Answer: (A)

Crude oil and coal come from different natural histories, and the key difference is the state of the end product. Crude oil forms from the heat and pressure acting on ancient organic matter (primarily microscopic marine organisms) buried in sediments, turning it into liquid hydrocarbons that can migrate through rocks. Coal forms from ancient plant material in swampy environments; over long burial, it is compressed and heated to become a solid, carbon-rich rock. So the essential distinction is that oil remains a liquid while coal ends up as a solid. The other options don’t fit because rapid evaporation of seawater doesn’t produce oil, coal isn’t formed by geothermal heat turning it into a gas, and oil and coal do not form in the same way.