The Respiratory System

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Across
  1. 3. The bones that protects your lungs
  2. 5. A 4 meter long tube in your throat
  3. 6. The opposite of oxygen
  4. 7. The net passive movement of molecules
  5. 10. How Co2 becomes red blood cells
  6. 12. Air passages inside the lung
Down
  1. 1. The smallest of the blood vessels
  2. 2. The sense of smell
  3. 4. Air passages that connect to the lungs
  4. 8. What humans breathe
  5. 9. A thin skeletal muscle at the base of the chest
  6. 11. The organ we use to breathe