1. Which of the following is the main organ of the circulatory system?

2. What type of circulation involves blood flow between the heart and the lungs?

3. Which chamber of the heart receives oxygenated blood from the lungs?

4. Which blood vessels carry oxygen-rich blood away from the heart?

5. What is the function of red blood cells (RBCs)?

6. Which valve prevents backflow of blood from the left ventricle to the left atrium?

7. Which of the following helps in maintaining unidirectional blood flow?

8. Which blood vessels have the thinnest walls to allow exchange of gases and nutrients?

9. Which component of blood helps in clotting?

10. Which of the following is the liquid part of blood?

11. What is cardiac output?

12. Stroke volume is defined as:

13. Which instrument is used to measure heart rate?

14. An increase in sympathetic nervous activity generally causes:

15. Which blood group is considered the universal donor?

16. Which blood group is known as the universal recipient?

17. The Rh factor is named after:

18. If a person has blood type A, they have:

19. A person with Rh-negative blood can receive blood from:

20. Which of the following combinations is unsafe during pregnancy?

21. Hemoglobin is found in:

22. What is the primary function of hemoglobin?

23. Low levels of hemoglobin can lead to:

24. Which mineral is essential for hemoglobin synthesis?

25. Normal blood pressure is approximately:

26. Systolic pressure refers to:

27. A person with high blood pressure is said to have:

28. Which instrument is used to measure blood pressure?

29. Regular exercise helps the heart by:

30. Exercise improves circulation by:

31. Which of the following is a long-term benefit of regular aerobic exercise?

32. Exercise can help reduce the risk of: