Across
- 5. salt content is above normal
- 6. how clear the water is
- 8. a common water pollutant
- 9. colorless, tasteless gas
- 10. bacteria in the intestinal tracts of mammals
- 11. maintaining healthy ecosystems
- 14. study of Earth's water
- 15. H2O
Down
- 1. material deposited by water,wind,etc.
- 2. a liquid flowing into a reservoir
- 3. animals without backbones
- 4. nursery for animals
- 7. organisms that live on the bottom floor of the ocean
- 12. organisms that need oxygen
- 13. elements with high atomic weights