Across
- 2. studies fossils
- 5. multicellular embryo
- 7. Related Genes
- 9. Outer layer
- 10. Diagram
- 14. Adapting
- 16. Eliminated
- 19. Fertilized egg
- 20. study of formation
Down
- 1. Mutation Rate
- 3. Early Embryo
- 4. Affects evolution
- 6. Middle layer
- 8. Mouth Develops First
- 11. Reproductive Success
- 12. Innermost layer
- 13. Populations evolve
- 15. Fossil Ages
- 17. educated guess
- 18. Second mouth