Final crossword puzzle

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Across
  1. 3. highest concentration,
  2. 4. pressure, cloudy,
  3. 7. and record, an examination,
  4. 9. inside of the earth,
  5. 10. water carbon dioxide.
  6. 14. fresh water,
  7. 15. the process of liquid changing,
  8. 19. drift Slowly moved,
  9. 20. boundaries, move apart,
  10. 21. waves, the first to reach,
Down
  1. 1. freezes,
  2. 2. altitude temp, distinguish layers,
  3. 5. surface, nearest,
  4. 6. energy release,
  5. 8. from oceans and lakes, water,
  6. 10. law, A pattern in nature,
  7. 11. measure,
  8. 12. mid-ocean ridge, underwater chain,
  9. 13. cold and warm,
  10. 16. 7 steps of
  11. 17. humidity, the measure of the amount,
  12. 18. normal reverse, movement of two blocks,