Across
- 3. water that has been used and now contains harmful substances
- 6. a person who uses science knowledge to design something in order to solve a problem
- 8. water in the form of an invisible gas
- 9. the solid part of earth
- 11. a group of parts that work together
- 12. he air that surrounds earth
Down
- 1. all of the living things on earth
- 2. the process in which substances change into different substances
- 4. process of a gas turning into a liquid
- 5. a supply of something that is useful
- 7. process of a liquid turning into a gas
- 10. all of the liquid water and ice on earth