Lungs and breathing

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Across
  1. 2. the gas we breathe in
  2. 5. lungs are protected by ...
  3. 6. the organ which helps us breathe
  4. 7. lungs are found in ...
Down
  1. 1. another name for trachea
  2. 3. the gas which makes up the most of the air
  3. 4. the organ system the lungs are part of