Science (086) — AI-generated practice question

Arteries — Thick, Elastic Walls:
Arteries carry blood away from the heart. The heart pumps blood under high pressure, so arteries need thick, elastic walls to withstand and absorb this pressure without bursting. The elasticity also helps maintain smooth blood flow.

Veins — Thinner Walls with Valves:
Veins carry blood back to the heart. By the time blood reaches the veins, pressure has dropped significantly, so thick walls are unnecessary. However, valves are essential to prevent the backflow of blood, ensuring it flows only in one direction — towards the heart.

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

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• The textbook directly states: "arteries have thick, elastic walls" because blood emerges from the heart under high pressure; veins "do not need thick walls because the blood is no longer under pressure" but have valves to ensure one-directional flow.
• Always link structure → function clearly. Examiners expect you to explain why, not just what.
• For 3 marks: award 1 mark for arteries' structure + reason, 1 mark for veins' structure + reason, 1 mark for correct direction of flow in each vessel.