Crossword

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Across
  1. 3. What pumps blood around the body
  2. 5. Number of lungs we have
  3. 8. Gas we breath out
Down
  1. 1. What we produce when we exercise
  2. 2. What are our lungs used for
  3. 4. What happens to our heart rate during exercise
  4. 6. Source of Oxygen
  5. 7. Gas we breath in