The Respiratory System

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Across
  1. 4. smaller tubes leading from the bronchi to the alveoli
  2. 5. also called the windpipe
  3. 6. protect the lungs
Down
  1. 1. sheet of muscle underneath the lungs that helps with inhalation and exhalation
  2. 2. large tubes leading to a lung each
  3. 3. large air sacs where gas exchange takes place