Respiratory System Crossword

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Across
  1. 5. small air passages inside the lungs
  2. 6. a muscle that helps control breathing
  3. 7. movement of oxygen and carbon dioxide between air and blood
  4. 10. protein in red blood cells that carries oxygen
  5. 12. breathing air into the lungs
  6. 13. the process of breathing and using oxygen to release energy
  7. 14. organs where oxygen and carbon dioxide are exchanged
Down
  1. 1. a waste gas removed from the body
  2. 2. tiny blood vessels surrounding the alveoli
  3. 3. the windpipe that carries air to the lungs
  4. 4. breathing air out of the lungs
  5. 8. tiny air sacs where gas exchange occurs
  6. 9. two tubes that branch from the trachea into the lungs
  7. 11. a gas needed by cells to produce energy