Biology

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Across
  1. 4. The liquid part of blood
  2. 6. Tiny blood vessels that deliver blood close to every tissue
  3. 7. A structure that allows fluid to flow in only one direction
  4. 9. Respiration that uses oxygen
Down
  1. 1. A tiny,air-filled space inside the lungs,also called alveolus
  2. 2. A red pigment found inside red blood cells,that transports oxygen
  3. 3. The movement of air in and out of the lungs
  4. 4. A thin and transparent membrane that sorrounds the lungs
  5. 5. A kind of sugar,used as an energy source by living cells
  6. 8. A substance that affects the way the body works