Give reasons:
Veins have valves at intervals in their inner lining whereas the arteries do not have valves.

Valves are present in the veins.

Why do only veins have valves and not arteries?

Veins are thin walled and have valves. Justify

Veins have valves which allow blood to flow only in one direction. Arteries do not have valves. Yet the blood flows in one direction only. Can you explain why?

Which one of the following does not have valves ?

A vein differs from the artery in having

Assertion(A): Arteries do not collapse, but veins collapse when they are cut through. Reason (R): Arteries do not have valves whereas veins have valves.

Read the assertion and reason carefully to mark the correct option out of the options given below: (a) If both the assertion and the reason are true and the reason is a correct explanation of the assertion (b) If both the assertion and reason are true but the reason is not a correct explanation of the assertion (c) If the assertion is true but the reason is false (d) If both the assertion and reason are false (e) If the assertion is false but reason is true Assertion : Heart valves resemble swing doors in action Reason : Valves are present in the heart chamber, at the opening of the heart into large arteries and veins.