Across
- 1. The study of life
- 6. The process plants use to make food using sunlight
- 7. The force that pulls objects toward Earth
- 9. The center of an atom
Down
- 2. The gas that humans need to breathe
- 3. The planet known as the Red Planet
- 4. The liquid that covers most of Earth’s surface
- 5. The closest star to Earth
- 8. The solid form of water