Across
- 4. fossils that existed for a short period of time across many regions
- 5. the law of _____________ that states that the rock closest to the top is the youngest rock
- 7. the age of something COMPARED to something else
- 9. a very long period in time, like the hadean ___
- 10. crucial animals for creating oxygen in early earth
Down
- 1. the time it takes for 1/2 of an unstable element to change into a stable one
- 2. when a rock cuts across another rock
- 3. the exact age of something
- 6. when a rock is inside another rock
- 8. true or fake: an intrusion is younger than the rocks around it