Crossword

12345678
Across
  1. 2. What pumps blood around the body
  2. 3. What we produce when we exercise
  3. 4. What happens to our heart rate during exercise
  4. 8. Gas we breath in
Down
  1. 1. What are our lungs used for
  2. 5. dioxide Gas we breath out
  3. 6. Source of Oxygen
  4. 7. Number of lungs we have