Question

Which of the following statements is true for blood capillaries?

• A. They have valves.
• B. They have a large lumen.
• C. They are thick blood vessels.
• D. They have very thin walls.

Answer 1

The correct option is D They have very thin walls.

Capillaries are small blood vessels. Unlike arteries, they have very thin walls. Unlike veins, they do not have valves. They have a small lumen as they are structurally very small.