Respiration

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Across
  1. 2. The scientific term for 'breathing in'.
  2. 7. _ _ _ _ _ _ _ _ _ exercise occurs when we use more oxygen than our heart and lungs can supply.
  3. 9. The process where plants release oxygen and make food from sunlight.
Down
  1. 1. The scientific term for 'breathing out'.
  2. 3. We need this to do respiration. It is also called 'O2'.
  3. 4. The _ _ _ _ _ _ _ _ _ _ _ _ _ _ system is the heart and lungs working together.
  4. 5. It is very important that we _ _ _ _ _ _ _ _ regularly to keep our heart and lungs healthy.
  5. 6. Our bodies are built up of trillions of microscopic units called _ _ _ _ _.
  6. 8. Our heart _ _ _ _ increases when we exercise intensely.
  7. 10. The organ that pumps blood around our body to supply our muscles and organs with oxygen and nutrients.