Across
- 2. The throat
- 5. Door that allows food, drink, and air into correct tubes
- 7. large proteins that contain four iron containing heme components
- 8. Lines the respiratory system with mucous cells.
- 9. The upside down tree
Down
- 1. the exchange of gases between the blood and alveolar air
- 3. Thin walled and surrounded by capillaries
- 4. Where air enters
- 6. Air in the alveoli