Across
- 4. rich deposits found in the Middle East
- 5. chemical compounds derived from oil
- 7. world's most abundant fossil fuel
- 8. primary source of energy on Earth
Down
- 1. energy from hot underground water or steam
- 2. process used by nuclear power plants to generate energy
- 3. energy produced from material of living organisms
- 6. the ability to do work or make a change