vocabulary

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Across
  1. 3. lighter element join together to form heavier elements is called what?
  2. 7. the largest land mass in earths history
  3. 9. the second longest period of time
  4. 14. the right age of something
  5. 15. the life force decreases over a sertant amount of time
  6. 16. big sheet of ice over mn
  7. 17. what happens when a star runs out of feul?
  8. 18. the formation of protons and neutrons
Down
  1. 1. happened to the earth five times
  2. 2. the biginning of the universe
  3. 4. the longest period of time
  4. 5. law of superposition
  5. 6. how to tell if an object is moving away from you
  6. 8. how to find the life expectancy of a star.
  7. 10. the death of a lot of species in a short time
  8. 11. small changes in temperature slowly
  9. 12. the shortest period of time
  10. 13. thought that the continents were puzzle pieces