Which chemical property of fossil fuels contributes to their classification as nonrenewable energy sources?

• A. They are formed over millions of years and cannot be replenished on a human timescale.
• B. They release oxygen when combusted.
• C. They are easily synthesized from carbon dioxide and water.
• D. They have a low energy content compared to renewable sources.

Answer: (A)

Verified step by step guidance

1. Understand the definition of nonrenewable energy sources: these are resources that cannot be replenished or regenerated on a human timescale once they are consumed.
2. Recognize that fossil fuels are formed from the remains of ancient plants and animals subjected to heat and pressure over millions of years, which means their formation process is extremely slow.
3. Analyze the options given: releasing oxygen when combusted is incorrect because combustion typically consumes oxygen rather than releasing it.
4. Consider the synthesis option: fossil fuels are not easily synthesized from carbon dioxide and water; this process is complex and not naturally rapid.
5. Evaluate the energy content: fossil fuels generally have a high energy content, so the statement about low energy content is incorrect. The key property is their formation time, making them nonrenewable.