The Respiratory System

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Across
  1. 3. Fast breathing, low blood carbon dioxide
  2. 4. The process of air leaving the lungs
  3. 5. Bones that provide physical protection to the heart and lungs
  4. 7. Small branches of airways connected to the alveoli
  5. 8. Opening to the trachea
Down
  1. 1. The windpipe
  2. 2. Passageway at the back of the throat
  3. 4. A flap that closes on top of the trachea
  4. 6. Small pouches that form grape-like clusters
  5. 7. Branches off of the trachea