Across
- 4. tubes Tubes which leads from windpipe to each lung
- 5. Bone structure which protects the heart and lungs
- 6. Muscle located under the lung
- 9. Letting air out of the lungs
- 10. Main organ of the respiratory system
Down
- 1. The process of producing energy using sugar and oxygen
- 2. Allows air to enter and leave the body
- 3. Filters the air we inhale and branches into the air tubes
- 7. Taking air into the lungs
- 8. A substance that moistens the air as well as trapping foreign substances