The Respiratory System

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Across
  1. 1. to keep our respiratory system healthy we should avoid _______ places
  2. 5. are millions of tiny air sacs in the lungs
  3. 6. protect the lungs
  4. 9. oxygen passes through the nose or mouth and passes through this tube
Down
  1. 2. flat sheet of muscle extending across the bottom of the rib cage
  2. 3. system that consists of the nose, the mouth, the trachea, and the lungs.
  3. 4. it is important to keep our respiratory system _______
  4. 7. two smaller tubes on each side of the lungs
  5. 8. filters the air that we breathe in