Across
- 2. a fossil that has bean dated
- 4. similar structures
- 7. old rock is deeper than new rock
- 8. early stage of animal development before the fetus
- 9. "the chemical of life"
Down
- 1. a structure with no purpose
- 3. comparing body parts
- 5. shows structure of animals that lived long ago
- 6. data base of all known fossils