Why do only veins have valves and not arteries?

Explanation

**Step-by-Step Solution:**

1. **Understanding Blood Flow in the Body**: Blood circulates through the body in a closed system, moving from the heart to various organs and back to the heart. This circulation involves arteries and veins.

2. **Role of Arteries**: Arteries carry oxygenated blood away from the heart to the body (except for the pulmonary artery, which carries deoxygenated blood to the lungs). The blood in arteries is under high pressure due to the force of the heart's pumping action.

3. **Role of Veins**: Veins return deoxygenated blood back to the heart (except for the pulmonary vein, which carries oxygenated blood from the lungs to the heart). The blood in veins is under lower pressure compared to arteries.

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