Across
- 2. a proposed answer to a question
- 5. the air that surrounds Earth
- 7. a group of atoms joined in a particular way
- 13. a scientist who studies stars, planets, and other objects in the universe
- 14. an arrangement of stars as seen from Earth
- 15. all the land on Earth
- 16. a scientist that studies ecosystems
- 17. the ability to make things move or change
Down
- 1. the invisible pull between Earth and other objects
- 3. a living thing, such as animals or plants
- 4. information that supports an answer to a question
- 6. all the water on Earth
- 8. to describe how something works or why something happens
- 9. water in the form of an invisible gas
- 10. an organism that breaks down dead organisms
- 11. the stuff that things are made of
- 12. all the living things on Earth