Respiratory System

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Across
  1. 2. What do we breathe out?
  2. 5. What wall does the oxygen and carbon dioxide push through?
  3. 7. any process that living things use to actively maintain fairly stable conditions necessary for survival
  4. 8. What organ is most vital to the respiratory system?
Down
  1. 1. What is the meeting point for the nose and mouth called?
  2. 2. What is the "Nose hair" that protects you from breathing anything unwanted in?
  3. 3. What do we breathe in?
  4. 4. What is another word for throat?
  5. 6. Tiny air sacks