Across
- 2. The bones in the mouth that help to bite and chew food.
- 9. The study of the past.
- 11. 1,000,000
- 13. The study of ancient life, especially fossils.
- 14. An animal with cold blood and a scaly skin, like a snake.
- 15. The remains of an ancient plant or animal preserved in rock.
- 16. Something that is new or has not existed for very long.
- 17. Something that shows what has happened in the past.
- 18. 1,000,000,000,000
- 19. 1,000,000,000
- 20. A small, six-legged animal with a hard outer shell.
Down
- 1. Something that has disappeared forever.
- 3. An animal that lives both in water and on land, like a frog.
- 4. An animal with hair that drinks milk when it is a baby.
- 5. A soft-bodied animal with a shell, like a snail or clam.
- 6. Science of the earth's land
- 7. Something that has existed for a long time.
- 8. The hard structures that support the body of animals.
- 10. The principle that younger rocks are usually found on top of older rocks.
- 12. Something confusing or difficult to understand.
- 21. A long period of time in history.