Across
- 4. flap of skin that stops food entering the trachea when swallowing.
- 6. respiratory medium for an insect(also respiratory medium for earthworm, mammals and amphibians.
- 7. a way to describe guard cells when a stomatal opening is open.
- 8. chitin lined air tubes.
- 9. box shaped structure above trachea. contains vocal cords.
- 10. the process of moving the respiratory medium over the respiratory surface to maintain a concentration gradient replacing a stale area high in CO2 with fresh oxygenated air.
Down
- 1. gas exchange surface of a fish.
- 2. holes in an insects exoskeleton which can open and close like valves to allow exchange of gases and reduce water loss.
- 3. palisade cells are elongated and densely packed together and contain many what?
- 5. a chemical substance which covers the surface of the alveoli. it reduces surface tension and prevents the alveoli from sticking together and collapsing when breaking out.