Across
- 4. flat discs with no nuclei.
- 7. red blood cells.
- 9. protects body from diseases.
- 11. carries blood to from heart.
- 12. exchange substances between blood and cells.
Down
- 1. prevents back flow of blood from Aorta into ventricles.
- 2. produces antibodies and destroys bacteria.
- 3. carries blood away from heart.
- 5. thick walls to pump blood put of heart.
- 6. prevents back flow from ventricles into atria.
- 8. contains haemoglobin.
- 10. white blood cells.