Respiratory System

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Across
  1. 2. muscle used for breathing
  2. 5. fluid build-up in air sacs, caused by altitude sickness
  3. 6. cavity where lungs sit
  4. 7. lack of oxgyen in tissues
  5. 8. keeps alveoli from collapsing
Down
  1. 1. opening with vocal cords
  2. 3. respiratory center of brain
  3. 4. whooping cough
  4. 9. pause in breathing during sleep