Across
- 2. find or learn sth. new
- 4. have inside
- 6. detailed
- 8. as a result
- 11. whem contrasted with
- 15. sharply
- 16. many years in the past
- 18. small animals with six legs, a hard body and often wings
- 19. N2
- 20. green things that get energy from sunlight
- 21. the hard material inside trees
Down
- 1. below 0 degrees Celcius
- 3. rock
- 5. water that has turned solid
- 7. move ahead to
- 8. normal
- 9. very big
- 10. a substance used in or produced by a chemical process
- 12. O2
- 13. the past participle of 'to freeze'
- 14. extinct reptiles that were often very, very large
- 17. understand