Jianna's Crossworld puzzle :)

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Across
  1. 2. Something that happens constantly
  2. 4. Change of frequency
  3. 7. a layer inside a planetary body below by a core and above by a crust\
  4. 10. Any class of chemical reactions
  5. 11. A real quantity having a value more than zero
  6. 14. Information or facts supporting a claim
  7. 16. A gigantic continent
  8. 17. The extremely hot center of Earth
  9. 18. German physicist, meteorologist, and explorer who introduced the theory of continental drift in 1915
Down
  1. 1. A large solid area of land
  2. 3. A country that mesosaurus fossils were found
  3. 5. The bodies of plants and animals buried in sediments
  4. 6. When plates move away from each other
  5. 8. An explanation for why things work or how things happen
  6. 9. When plates move towards each other and collide
  7. 12. A extremely deep valleys, just in the ocean and not land
  8. 13. A real quantity having a value less than zero
  9. 15. The outer layer of Earth