Across
- 2. Blood vessels that carry blood away from the heart.
- 4. Site of gas exchange in the lungs.
- 7. Process of exchanging gases in the body.
- 9. Part of the throat behind the mouth and nasal cavity.
- 10. Also known as the windpipe.
Down
- 1. Blood vessels where exchange with body cells occurs.
- 3. Protein in red blood cells that carries oxygen.
- 5. Blood vessels that return blood to the heart.
- 6. Muscle that plays a key role in breathing.
- 8. Essential gas provided by the respiratory system.