Respiratory System

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Across
  1. 2. Part of brain that controls breathing
  2. 4. Carries oxygen in blood
  3. 5. The process of breathing
  4. 6. Bone that protects the lungs
  5. 7. The gas essential for life
Down
  1. 1. Artery that leads to lungs
  2. 3. The muscle that separates the chest cavity from the abdomen