Across
- 4. cells responsible for carrying oxygen
- 6. wind pipe
- 7. when oxygen enters the lungs
- 8. little hairlike organelles
- 9. sticky substance that helps trap particles and microbes
Down
- 1. tiny air sacs in the lung where gas exchange occurs
- 2. when air leave the lungs
- 3. tiny branches in with the bronchus divides
- 5. muscle that helps us breathe