respiratory system

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Across
  1. 1. contains cells
  2. 4. plural form of bronchus.
  3. 6. any of the minute branches into which a bronchus divides.
  4. 8. membrane-lined cavity behind the nose and mouth
  5. 9. :a dome-shaped muscular partition
Down
  1. 2. helps you breath
  2. 3. large membranous tube reinforced by rings of cartilage: flabby skin surrounding something
  3. 5. breathes oxygen
  4. 7. bony frame formed by the ribs round the chest