NDA (II) 2025 General Ability Test · Question 135 of 147

Correct — B, the pulmonary-vessel statement is the one that is NOT correct. It claims pulmonary arteries carry oxygenated blood and pulmonary veins carry deoxygenated blood, but the truth is the exact reverse: the pulmonary artery carries deoxygenated blood from the heart to the lungs, and the pulmonary vein carries oxygenated blood from the lungs back to the heart. These are the famous exception to the general rule that arteries carry oxygen-rich blood, which is why the reversed statement is false and is the answer to a 'NOT correct' question.

• (a)Arteries carry blood away from heart while veins bring blood towards the heart — This is a true statement — the defining feature of arteries and veins is the direction of flow relative to the heart. Being correct, it cannot be the answer to a 'NOT correct' question.
• (c)Arteries have thicker and more elastic walls compared to veins in general — This is true — arteries carry blood at high pressure, so they have thick, elastic muscular walls, whereas veins are thinner-walled. A correct statement, so not the answer.
• (d)Arteries do not have valves but veins do have valves — This is true — veins have one-way valves to stop blood pooling and flowing backward against gravity, while arteries rely on pressure and elastic recoil and generally lack such valves. Correct, so not the answer.

Arteries carry blood away from the heart and veins return it to the heart. Because arteries handle high-pressure output, they have thick, elastic walls and no valves along their length; veins carry blood at low pressure and use one-way valves to keep it moving toward the heart. The usual rule that arteries carry oxygenated blood has two well-known exceptions in the pulmonary and umbilical circulations.

This is a 'find the false statement' question, so three of the four options are true and only one is wrong. The safe strategy is to test each general rule and then check the exceptions: the direction rule (a), the wall-thickness rule (c) and the valve rule (d) all hold, so the error must lie in the pulmonary-vessel claim, which reverses which vessel is oxygenated.

• The pulmonary artery carries deoxygenated blood from the heart to the lungs.
• The pulmonary vein carries oxygenated blood from the lungs back to the heart.
• Arteries have thick elastic walls and usually no valves; veins are thinner-walled and have one-way valves.
• Arteries carry blood away from the heart; veins carry it toward the heart.

• The rule 'arteries carry oxygenated blood' fails for the pulmonary artery (deoxygenated) and pulmonary vein (oxygenated).
• In a 'NOT correct' question, three statements are true — read carefully so a familiar true fact does not tempt you.

Asked to pick the incorrect statement about arteries and veins, or to identify which vessel carries oxygenated or deoxygenated blood.

• practice — not a real PYQ

  Which one of the following blood vessels carries oxygenated blood?

  • (a)Pulmonary artery
  • (b)Pulmonary vein
  • (c)Vena cava
  • (d)Renal vein

  Answer(b) Pulmonary vein — it carries oxygen-rich blood from the lungs back to the heart, the exception to the usual vein rule.

• practice — not a real PYQ

  One-way valves that prevent the backflow of blood are a characteristic feature of

  • (a)Arteries
  • (b)Veins
  • (c)Capillaries
  • (d)Arterioles

  Answer(b) Veins — their valves keep low-pressure blood moving toward the heart and stop it flowing backward.