Across
- 2. population
- 5. preservation
- 7. Earth
- 8. poverty
- 9. key
- 11. danger
- 13. storm
- 15. cancer
- 18. ecotourism
- 19. extincion
- 20. source
Down
- 1. ecosystem
- 3. crisis
- 4. sickness,illness
- 6. overpopulation
- 10. consequence
- 12. feedback
- 14. allergy
- 16. recycling
- 17. hunger