Circular crossword

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Across
  1. 3. The organ that is responsible for oxygen entering the blood.
  2. 5. Released from our bodies when we breathe out
  3. 7. What can circle around the earth 2 1/2 times
  4. 9. Supplies blood to the heart muscle
Down
  1. 1. Smallest blood vessels in the vascular system
  2. 2. This system is responsible for flowing blood nutrients and gasses through the body
  3. 4. A big pump in the body
  4. 6. The number of seconds
  5. 7. Transports nutrients, hormones and oxygen around the body
  6. 8. The number of months red blood cells last