Across
- 4. (two words) the system we are studying.
- 5. The main organ of the respiratory system
- 7. The process of releasing energy.
Down
- 1. The very small blood vessels in the lungs.
- 2. (two words) The toxic waste gas of the body.
- 3. The sceintific name for the windpipe.
- 6. The tubes leading to the lungs.
- 8. The microscopic air sacs in the lungs.