Across
- 2. The center of an atom
- 8. The process plants use to make food
- 11. The force that pulls objects to Earth
- 13. The biggest planet in the solar system
- 14. The organ responsible for thinking
- 15. The star at the center of our solar system
Down
- 1. The bones that protect the brain
- 3. The only planet with life
- 4. The red planet
- 5. The largest organ in the human body
- 6. The closest planet to the sun
- 7. The tube that carries food to the stomach
- 9. A gas that humans need to breathe
- 10. The planet with rings
- 12. The organ that pumps blood