Across
- 3. The science of the relationships between organisms and their environments.
- 5. We cannot live without it.
- 6. Source of pollution from factories.
- 7. Maamora in Morocco, for example.
- 9. Not artificial.
- 10. opposite of dead.
Down
- 1. Turning waste materials into new products.
- 2. Trees for example.
- 4. The air in big cities is usually _________.
- 8. When there isn't any_________, there is drought.