Across
- 3. required
- 6. light emitted by some substances after being exposed to light
- 9. a unit apart or by itself
- 11. of great value
- 13. very small
- 15. many kinds of life
- 17. designed for people to live in
- 20. full of or swarming with
- 21. throw in various directions
- 23. able to adjust
Down
- 1. a thin barrier
- 2. able to be used for a practical purpose
- 4. a scent used by animals
- 5. so small it can be seen only with a microscope
- 7. to transfer, pass
- 8. a nerve cell
- 10. the chemical in hot peppers that gives a burning sensation
- 12. to get smaller
- 14. movement from one region to another
- 16. a person who offers to do a task
- 18. the central part of something
- 19. not exact or accurate
- 22. animals that begin life in water then live on land
- 24. relating to the earth