What are fossil fuels?

• A. Coal, oil, natural gas, and other fuels that are ancient remains of plants and animals
• B. Solar and wind energy
• C. Hydroelectric power
• D. Nuclear fuels

Answer: (A)

Fossil fuels are energy-rich substances formed from the remains of ancient plants and animals that were buried and subjected to heat and pressure over millions of years. Coal, oil, and natural gas are the main examples. They’re used to generate electricity, run farm machinery, and manufacture products essential to agriculture, but they’re nonrenewable because they take such a long time to form.

The other energy sources mentioned don’t fit because they come from different processes: solar and wind energy come from the sun and wind, not ancient organic matter; hydroelectric power relies on moving water; nuclear fuels involve radioactive materials used in reactors.