Science (086) — AI-generated practice question

Arteries carry blood away from the heart under high pressure (generated by ventricular contraction). Therefore, they need thick, elastic walls to withstand and accommodate this pressure without bursting.

Veins carry blood back to the heart and the blood is no longer under high pressure. Hence, thick walls are not needed. Instead, veins have valves to ensure blood flows only in one direction.

Source: Chapter 5, Section 5.4.1 – The tubes – blood vessels

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• Examiners expect two contrasting points: one for arteries (high pressure → thick elastic walls) and one for veins (low pressure → no thick walls, but valves present).
• Mentioning valves in veins is a bonus point that shows thorough understanding.
• Keep the cause-effect link clear: because the blood is under high/low pressure, therefore the wall structure is as it is.