Earth and Space

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Across
  1. 3. the sudden occurrence of a discharge of volcanic material
  2. 6. the fourth period of the paleozoic period
  3. 7. the continuous physical force exerted against an object
  4. 10. part of the skeletal system
  5. 11. rock formed from consolidated clay sediments
  6. 12. the star around which the earth orbits
  7. 13. the occurrence in which a large number or all of a certain species dies off
  8. 15. a person who studies fossils
  9. 16. a group of organisms consisting of similar individuals capable of exchanging genes and interbreeding
Down
  1. 1. the gradual destruction or diminution of something by wind, water, or other natural agents
  2. 2. the second period of the paleozoic era
  3. 4. a change or the process of change by which a species becomes better suited to its environment
  4. 5. a discharge of electricity
  5. 8. the process in which bones are replaced by minerals to form rocks
  6. 9. a long and distinct period of history with a particular feature or characteristic
  7. 14. the remains or impression of an animal preserved in rock