Across
- 2. relaxes when you exhale
- 4. the waste that we exhale
- 7. air ways to the lungs
- 8. pipe that connects to your lungs
- 10. where breathing starts
- 11. the smallest blood vessel
Down
- 1. high and low concentration
- 3. the main source of respiration
- 5. what we breathe
- 6. air sacs
- 7. splits air to each lung
- 9. keeps your lungs safe