Across
- 5. A scientist that studies fossils
- 7. this era consisted of one-celled animals, bacteria, and jellyfish
- 9. saying someone is younger than their father is using _____ age
- 10. 65.5 million years ago to present day eon
Down
- 1. index ___ are also used to determine the age of rocks
- 2. A scientist that studies the Earth's crust
- 3. a rock is younger because it is ____ between multiple other layers
- 4. the law of ___ is a law used when a layer is above a layer, making the bottom layer older than the upper layer
- 6. precisely finding a fossil's age
- 8. Earth's first era