The Respiratory System

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Across
  1. 3. The muscle beneath the lungs that helps breathing
  2. 8. The main breathing organs
  3. 9. The waste gas removed when breathing out
Down
  1. 1. The gas needed by body cells for energy
  2. 2. The tube that carries air from the throat to the lungs
  3. 4. The process of exchanging gases in the body
  4. 5. Large tubes connecting the trachea to the lungs
  5. 6. Small tubes branching from the bronchi
  6. 7. Tiny air sacs where oxygen enters the blood