Across
- 4. If you know that "respiration" means "_____", then you can already guess what the respiratory system does
- 5. We breathe out _____ dioxide, and plants take it in
- 7. Plants release _____, and we breathe it in
- 9. Our _____ expand and contract like balloons as we breathe
- 10. To become small again after expanding
Down
- 1. The muscle that allows your lungs to expand and contract; it shrinks as your lungs grow and it grows as your lungs shrink
- 2. Little tubes in your lungs; Clue: Bronchitis
- 3. What scientists call your windpipe
- 6. To blow up like a balloon
- 8. Sacs inside the lungs that get oxygen and carbon dioxide to and from the blood as we breathe in and out