Earth and Space

2. the sudden occurrence of a violent discharge of steam and volcanic material
4. during this mass extinction is the disappearance of the dinosaurs
5. a solid inorganic substance of natural occurrence
6. the action or process of adapting or being adapted
9. what makes the sedimentary rock? Pressure the continuous physical force exerted on or against an object by something in contact with it
11. a long and distinct period of history with a particular feature or characteristic
12. rock formed from consolidated clay sediments
14. this mass extinction lost 70% of marine species
15. any of the pieces of hard, whitish tissue making up the skeleton in humans and other vertebrates
16. the process of eroding or being eroded by wind, water or other natural agents
17. during this mass extinction 50% of animals species disparaged
18. 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

1. discharge of electricity
3. this mass extinction is the disappearance of more than 50% of fish, sponges and corals
7. is the mass extinction when 96% of marine species and 75% species disappeared
8. the process by which organic matter exposed to minerals over a long period is turned into a stony substance
10. a specialist in paleontology
13. one species disappear completely