Fact 1: Constriction occurs when the muscular walls of blood vessels contract.

Fact 2: Caffeine constricts blood vessels.

Given the two facts above, answer the question "What does caffeine make blood vessels do?" with the following options: 
- reduce
 - sweating
 - reduced heat
 - Dehydration
 - survive
 - contract
 - It expands
 - Rise


 

      contract   