Across
- 7. clue
- 10. derives the organic compounds
- 11. a biological community
- 12. occupied by living organisms.
- 14. the branch of biology
- 15. key for the identification
- 18. clue
- 19. infestation by a parasite.
- 20. resulting from living things
- 21. adapted to their environment
Down
- 1. clue
- 2. devoid of life; sterile
- 3. habitat after a major
- 4. action of populating an area.
- 5. produces organic compounds
- 6. interdependent food chains
- 8. ecological succession
- 9. association between two
- 13. living in the same place
- 16. both organisms involved.
- 17. clue