Across
- 4. from 146 to 66 million years ago
- 8. a hard yellow or brown material that comes from coniferous (pine) trees. Sometimes extinct animals are found inside.
- 9. one bone of the backbone
- 10. breaking down over time
- 12. able to see light through
Down
- 1. young
- 2. clearly separated
- 3. to make something last a long time
- 5. joined together
- 6. a substance that gives color to tissues and skin
- 7. before written history
- 11. for decoration
- 13. a change in the genetics of an animal species over many generations