Across
- 4. Main component of natural gas.
- 7. Element found in coal along with carbon.
- 9. Unrefined oil from the ground.
- 10. Action taken through mud and sand to reach oil
- 11. Combustible black sedimentary rock.
- 14. Heavy element used in nuclear fission.
- 15. Trace gas found in natural gas.
Down
- 1. Second largest component in natural gas (4-5%).
- 2. What dead plant matter turns into before coal.
- 3. Main element fossil fuels are made of.
- 5. Formed from remains that sedimented on ocean floors.
- 6. Fuel used in internal combustion engines.
- 8. Fuel used in jet engines.
- 12. Contaminant in coal that causes pollution.
- 13. Another trace gas in natural gas.