Across
- 4. makes windmills turn
- 7. balloons filled with
- 8. produce CFC
- 13. plants prepare food
- 14. energy from earth
- 15. removal of waste
- 17. our galaxy
- 19. unit of force
- 20. hottest planet
Down
- 1. biological mass
- 2. speed with direction
- 3. thermometer
- 5. length of shortest path travelled by a body
- 6. first element
- 9. path of light energy
- 10. plant science
- 11. smallest unit of matter
- 12. bending of light
- 16. Disease on global scale
- 18. eyeglasses