The Cardiovascular and Respiratory System

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Across
  1. 1. The muscular organ that pumps blood through the circulatory system
  2. 4. Tiny, disk-shaped cell that carries oxygen in the circulatory system
  3. 6. Tiny, thin-walled blood vessels where oxygen and nutrients are exchanged with tissues
  4. 7. Primary organ of the respiratory system
Down
  1. 2. The body's largest artery and a key part of the circulatory system
  2. 3. The main tube through which air enters the lungs
  3. 5. The gas essential for respiration