Across
- 5. To change the frequencies of alleles in a population
- 7. The older fossils are deeper than younger
- 8. The sequence of changes among species
- 9. The formation of fossils as rock replaces tissue
- 10. The complete disappearance of a species
- 11. The order things occurred
- 12. The study of the structures of organisms and the parts
- 13. the remains of organisms and the layers they are found
Down
- 1. The rate of difference
- 2. Mineralized remains of animals or plants
- 3. Looking at chemicals to determine the age
- 4. When organisms are from a single ancestor
- 6. layers of rock that are deposited