Across
- 2. nitrogen sunlight pollution
- 4. running water power
- 6. can be replaced
- 7. tectonic activity power plant
- 9. mineral rocks
- 10. uranium
- 11. replanted vegetables
- 12. energy from the Sun
Down
- 1. once they're gone they're gone
- 3. pH below 5.6
- 5. wood alcohol
- 8. cutting too many trees