Across
- 6. The uptake of molecular oxygen from the environment and the discharge of carbon dioxide to the environment.
- 7. Blood cells that perform the function of destroying disease-causing microorganisms.
- 9. Allows air to pass to and from lungs.
Down
- 1. Blood that carries an abundant amount of oxygen.
- 2. A column-shaped cell found in the respiratory and intestinal tracts, which secretes the main component of mucus.
- 3. A hollow, muscular organ that pumps blood throughout the body.
- 4. A thick, slippery substance produced by the body.
- 5. Main organs of the respiratory system.
- 8. Upper part of torso.