Across
- 4. What is the chemical symbol for water?
- 8. What planet is known as the Red Planet?
- 9. What force pulls objects toward Earth?
- 10. What is the center of our solar system?
Down
- 1. What is the study of living things called?
- 2. What is the study of matter and energy called?
- 3. What organ pumps blood in the human body?
- 5. What gas do humans need to breathe?
- 6. What is the largest planet in our solar system?
- 7. What is the hardest natural substance on Earth?