Across
- 3. Unavoidable
- 4. Important
- 5. Saving or protection
- 8. Sediment
- 11. A narrow valley
- 13. From time to time
- 15. Increase rapidly in number
- 16. Raised land
Down
- 1. Safety measures
- 2. Native or original
- 6. Process of weathering away
- 7. The quality of air in a place
- 9. An area controlled by powerful country
- 10. Insufficient
- 12. Encouragement/motivation
- 14. unpopulated