Across
- 3. breathing out
- 5. oxygen enters through here
- 6. this lung is smaller
- 9. what we breathe out
- 10. underneath the lungs
Down
- 1. breathing in
- 2. humans do this 20,000 times a day
- 4. can float on water
- 7. where air passes down
- 8. what we breathe in