The study of blood moving through the circulatory system.

• A. Hematology
• B. Cardiology
• C. Physiology
• D. Hemodynamics

Answer: (D)

The main idea is how blood moves through the circulatory system and what governs that movement. That focus is called hemodynamics, which examines the forces and factors that drive flow—heart-generated pressure, vascular resistance, vessel diameter, blood viscosity, and how these change with activity or disease to affect perfusion. Hematology deals with the blood’s components like cells and clotting factors, not the movement itself. Cardiology studies the heart and its diseases, while physiology is the broader study of how body systems work, including circulation, but not the specific mechanics of blood flow. So this term best captures the study of blood moving through the circulatory system.