Across
- 2. The planet known as the Red Planet.
- 3. The longest river in the world
- 5. The hardest natural substance on Earth
- 7. The study of stars and planets
- 9. The superhero known as the "Man of Steel".
- 10. A natural satellite that orbits Earth
Down
- 1. The world's largest ocean
- 4. The explorer who discovered America in 1492.
- 6. A polygon with six sides.
- 8. The branch of mathematics that deals with shapes and angles.