Metabolism Crossword

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Across
  1. 3. The ability to do work
  2. 4. A molecule with breath in
  3. 6. A group of atoms joined in a particular way
  4. 9. Only oxygen can enter this system
Down
  1. 1. Where the heart is and blood flows
  2. 2. The body's use of molecules for energy and growth
  3. 5. A system where food is broken down
  4. 7. Breaks down into amino acids
  5. 8. Breaks down into glucose