Across
- 2. billion
- 3. extinct
- 5. darwin
- 8. competition
- 10. mutations
- 12. cannot
- 14. cladogram
- 15. random
- 16. fossil
- 17. fertile
- 18. vestigial
- 19. population
Down
- 1. reproduction
- 3. environment
- 4. ancestor
- 6. homologous
- 7. evolution
- 9. Galapagos
- 11. natural selection
- 13. theory