Atherosclerosis involves the buildup of which substance inside arteries?

• A. Blood
• B. Plaque
• C. Oxygen
• D. Fuel

Answer: (B)

The key idea is that atherosclerosis is defined by the buildup of plaque inside the arteries. This plaque is a mix of cholesterol-rich lipids, inflammatory cells, calcium, and fibrous tissue that accumulates on the arterial walls, gradually narrowing and stiffening the vessel. Blood simply flows through the arteries, and oxygen is carried by that blood; neither of those materials deposits in the artery wall as part of atherosclerosis. The plaque’s growth reduces blood flow and, if it ruptures, can trigger a clot that blocks the artery, leading to events like heart attack or stroke. Understanding that the problem is lipid-rich, inflammatory plaque explains why high cholesterol, smoking, high blood pressure, and diabetes raise risk and drive the disease forward.