Respiratory System

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Across
  1. 1. carries oxygen to the rest of the body
  2. 3. thin muscle that contracts to make us breathe
  3. 5. to breathe out
  4. 6. you have two of them and they help you breathe
Down
  1. 2. the fuel in the air we breathe
  2. 4. to breathe in
  3. 7. it's on the tip of my ________