Earths changing system

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Across
  1. 1. the variety of life in the world or in a particular habitat or ecosystem.
  2. 4. spreading the process of new crust forming at a ridge and pushing older crust out
  3. 7. when all the species have died out
  4. 8. dating determining the age of rocks based on the decay of the elements
  5. 9. earth forces forces that change the surface of the earth from within; i.e. divergent, convergent, and transform boundaries
Down
  1. 2. species species that are not native to a specific location and have a tendency to spread to a degree believed to cause damage
  2. 3. number of species in an area
  3. 5. the length of time it takes for one-half of a radioactive element to change into another element
  4. 6. earth forces forces that change the surface of the earth from outside; i.e. humans, erosion, and weathering