Earth and Space

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Across
  1. 1. First period of the Mesozoic Era
  2. 3. Essential for the emergence of life, destructive if you live in a certain city in italy
  3. 6. All vertebrates have these
  4. 7. Force applied on an object
  5. 9. Expert on prehistoric life
  6. 11. Energy found coming from the sky in bolts
  7. 12. A change made to an organism to suit a new environment
  8. 13. Type of rock fossils are most commonly found in
  9. 18. Large period of time. There are only three in earth's history
  10. 19. Period of time in the Paleozoic Era, ending in the first mass extinction
Down
  1. 2. Layer of rock with the came characteristics
  2. 4. Star that is a possible energy source in the emergence of life on earth
  3. 5. Large decrease in the amount of life, 5 of these have occurred in earth's history
  4. 8. Petrified bones
  5. 10. Conversion of organic material into stone
  6. 13. A group of similar animals capable of breeding with each other
  7. 14. The mass extinction at the end of this period created the K/T boundary
  8. 15. Process in which rock is removed from the earth's surface by wind or water
  9. 16. Period of time ending in the disappearance of 70% of marine species
  10. 17. Period whos mass extinction caused the disappearance of 96% or marine species and 75% of all land species