Across
- 5. A natural satellite that orbits a planet
- 7. The process by which a caterpillar becomes a butterfly
- 8. The organ that allows humans to breathe
- 12. The change of a liquid to a gas
- 13. A gas that plants use to make food during photosynthesis
- 14. The study of matter and its properties
- 15. The force that resists motion between two surfaces
Down
- 1. A substance made up of two or more elements chemically joined
- 2. The force that pulls objects toward the Earth
- 3. A scientist who studies living organisms
- 4. The organ in the human body that pumps blood
- 6. The smallest unit of life
- 9. Energy that comes from the sun
- 10. A group of stars forming a pattern in the sky
- 11. The natural home of an animal or plant