Across
- 1. tubes forming the respiratory system
- 3. where cellular respiration takes place
- 6. protective secretion of the mucus membranes
- 8. collapsed lung
- 9. keeps alveoli from collapsing
Down
- 2. the uppermost cartilage of the larynx
- 4. the movement of gases between air & blood
- 5. contains vocal cords
- 7. tubes from trachea to lungs