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