The Respiratory System

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Across
  1. 3. The process by which the brain uses low oxygen levels as the signal to breathe.
  2. 6. The main site of gas exchange.
  3. 7. Breathing out.
  4. 8. High Carbon Dioxide Levels caused by inadequate ventilation.
  5. 9. The Trachea splits into these two main tubes.
Down
  1. 1. Produces sound through the vocal cords.
  2. 2. How many respiratory Tracts are there?
  3. 4. Breathing in.
  4. 5. Low oxygen levels which lead to respiratory failure.