Across
- 2. ___ blood cells fight infection
- 5. groups of tissues working together
- 10. made up of all the organ systems
- 12. groups of cells working together
- 13. system which makes blood cells
- 15. ____ blood cells carry oxygen through the blood
- 16. carry blood to the heart
- 18. circulates substances through the body
- 19. groups of organs working together
- 20. pumps blood
- 21. system which controls other body systems
Down
- 1. responsible for gas exchange
- 3. carry blood away from the heart
- 4. helps the body move
- 6. balanced internal conditions
- 7. system that removes liquid waste
- 8. food does not pass through these organs
- 9. breaks down food
- 11. made of skin, hair, and nails
- 14. the __ nervous system has the brain and spine
- 17. heart rate _____ when the body needs more O2 delivered to tissues