Across
- 3. A waste product of respiration that can be reused for photosynthesis, but breathed out by animals.
- 6. A molecule that supplies energy for cellular reactions.
- 8. Tiny hairs which move in a wavelike motion to remove dust.
- 9. Main organs of the respiratory system.
- 10. Another word for windpipe.
- 11. Tiny sacs within the lungs where gaseous exchange occurs.
Down
- 1. Taking air into the lungs
- 2. The process of which a substance moves from a high concentration to a low concentration.
- 4. Bone structure which protects the heart and lungs.
- 5. Letting air out of the lungs
- 7. A substance that warms and moistens the air as well as trapping foreign substances.