Across
- 4. a gas that is expelled from the body by the respiratory system
- 5. a wall of muscle that separates the chest and abdomen in humans and certain animals
- 7. the tube that carries air to the lungs in humans and other animals that breathe air; windpipe
- 9. main organs of the respiratory system. They bring oxygen to the body and get rid of carbon dioxide
- 10. blood vessels that carry blood away from the heart
Down
- 1. the red liquid containing oxygen and nutrients that pumps through the veins and arteries of humans and many other animals
- 2. a tiny blood vessel where substances are exchanged between the blood and the body cells
- 3. blood vessels that carry blood back to the heart
- 6. the regular beating of the arteries that is caused by the beating of the heart
- 8. the organ that pumps blood through the body of a person or animal