Which of the following has thickest walls?Select an answerAArteriesBVeinsCCapillariesDBoth arteries & veins have same wall dimension

The answer is A. Arteries.

Arteries have the thickest walls among arteries, veins, and capillaries. This is because arteries are the blood vessels that carry oxygenated blood away from the heart to the body, and they need to withstand the high pressure of blood being pumped from the heart. The walls of arteries are made up of three layers, with the middle layer being thick and muscular to accommodate the pressure of the blood.

On the other hand, veins carry deoxygenated blood back to the heart and do not need to withstand as much pressure, so their walls are thinner. Capillaries, which connect arteries and veins, have the thinnest walls to allow for the exchange of oxygen and carbon dioxide between the blood and body tissues.