Earth and Space

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Across
  1. 3. a solid inorganic substance of natural occurrence
  2. 6. discharge of electricity
  3. 10. the process by which organic matter exposed to minerals over a long period is turned into a stony substance
  4. 11. one species disappear completely
  5. 12. this mass extinction is the disappearance of more than 50% of fish, sponges and corals
  6. 14. a specialist in paleontology
  7. 15. during this mass extinction 50% of animals species disparaged
  8. 17. any of the pieces of hard, whitish tissue making up the skeleton in humans and other vertebrates
  9. 18. is the mass extinction when 96% of marine species and 75% species disappeared
Down
  1. 1. remains or impression of a prehistoric organism preserved in petrified form or as a mold or cast in rock Sun the star around which the earth orbits
  2. 2. what makes the sedimentary rock? Pressure the continuous physical force exerted on or against an object by something in contact with it
  3. 4. the sudden occurrence of a violent discharge of steam and volcanic material
  4. 5. this mass extinction lost 70% of marine species
  5. 7. the action or process of adapting or being adapted
  6. 8. rock formed from consolidated clay sediments
  7. 9. a long and distinct period of history with a particular feature or characteristic
  8. 13. the process of eroding or being eroded by wind, water or other natural agents
  9. 16. during this mass extinction is the disappearance of the dinosaurs