Puzzle

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Across
  1. 1. – Oxygen-carrying fluid
  2. 6. – Signal-carrying tissue
  3. 7. – Body control center
  4. 8. – Smallest unit of matter
  5. 9. – Group of similar cells
Down
  1. 2. – Body part with a function
  2. 3. – Breathing organ
  3. 4. – Basic unit of life
  4. 5. – Blood-pumping organ
  5. 7. – Hard body tissue