Coal, oil, and natural gas are examples of which type of fuels?

• A. Nuclear
• B. Fossil
• C. Bio
• D. Solar

Answer: (B)

The main concept here is how fuels are categorized by their origin. Coal, oil, and natural gas are fossil fuels because they come from ancient plant and animal matter that was buried and transformed by heat and pressure over millions of years. This long formation process means they are nonrenewable on human timescales, so we rely on them as energy sources for a long period but they will eventually run out. When burned, these fuels release stored energy and also CO2 into the atmosphere.

They’re not nuclear fuels, which rely on fission of heavy elements like uranium. They aren’t solar, which is energy captured directly from the sun. They aren’t biofuels in the sense of being derived from recent, renewable biological sources. So the fossil fuels label best fits coal, oil, and natural gas.