Crossword

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Across
  1. 2. largest country in the world
  2. 3. syrup-producing tree
  3. 4. egg-laying mammal
  4. 5. month of christmas
  5. 11. air around the Earth
  6. 12. inverse of multiplication
  7. 14. first element
  8. 16. the science of the Earth
  9. 17. percussion instrument with keys
  10. 18. women's history month
Down
  1. 1. measure of temperature
  2. 3. the study of numbers
  3. 6. planet beyond Earth
  4. 7. currency of England
  5. 8. spiny little mammal
  6. 9. king of Olympus
  7. 10. possible democratic candidate
  8. 13. an apple fell on his head
  9. 15. most northern state in the U.S.