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