Natural Wealth
Across
- 3. Black rock fuel
- 5. Fertile growing layer
- 7. Organic fuel material
- 8. Rich upper soil layer
- 10. Mineral-rich rock
- 12. Essential liquid resource
- 13. Conductive red metal
- 15. Earth's heat energy
- 17. Underground water layer
Down
- 1. Nuclear fuel element
- 2. Aluminum source ore
- 4. Harvested tree wood
- 5. Oil/gas bearing rock
- 6. Sun renewable power
- 9. Decayed plant fuel
- 11. Low-grade brown coal
- 12. Forest building material
- 14. Fossil fuel liquid
- 16. Invisible fossil fuel