Across
- 2. A part of respiratory tract.
- 7. Network of blood vessels surrounding alveoli.
- 9. A substance in cigarette smoke that can cause addiction.
- 10. A condition of damaged alveoli.
- 12. Process of water molecules diffuse from the high concentration region to low concentration region through semi-permeable membrane.
- 14. The sugar that broken down during cellular respiration.
- 17. A colourless and odourless gas.
- 18. In the breathing mechanism model, the rubber sheet represent the _____.
Down
- 1. Place where the gaseous exchange occurs.
- 3. An unstable compound and bright red in colour.
- 4. Cancer causing chemical substances.
- 5. One of the harmful substances in the air.
- 6. The skin of frogs is thin and very _____ to gas.
- 8. concentration of oxygen in the air is lower at a ____ altitude.
- 11. At night or on a hot day, the guard cells become _____ and straight.
- 13. The respiratory system of insects.
- 15. Pathway of air into the nasal cavity.
- 16. This happens to the intercostal muscles during inhalation.