Across
- 5. Able to be maintained
- 8. Trash that is left lying in public places
- 10. Part of biology that deals with the relationships of organisms and how they relate
- 12. The layer of gas that surrounds the Earth
- 13. An area trash is disposed of
- 14. A population that has no living members left
- 16. Relating to living matter
- 18. Maintain something in its original state
- 20. A gas that protects us from harmful UV radiation
Down
- 1. A biological community where organisms interact
- 2. Reusing discarded material to make it into a product of higher value
- 3. To contaminate something with a toxic substance
- 4. Discharge of gas or radiation
- 6. The surroundings in which an organism lives
- 7. Can be used without running out
- 9. Convert trash into useful material
- 11. The natural home or environment of an organism
- 15. Prevent something from being harmed
- 17. Decayed material used for fertilizing plants
- 19. Relating to the Sun