Answer the following question: Fact 1: Dilation occurs when cell walls relax. Fact 2: An aneurysm is a dilation of a blood vessel. Given the two facts above, what relaxes, thereby causing aneurysms?

(I) layers of fat (II) Veins and arteries. (III) sweating (IV) matter vibrating (V) blood vessels (VI) the skin (VII) Chemical energy (VIII) sensory neurons
Answer:
(V)