This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Which vessel regulates blood flow? 
Select and explain. 
A. Aery, B. Aerioles, C. Venules, D. Capillaries
B: Aerioles
Answer: B: Aerioles 
Explanation: Ans. b' aerioleDistribution of blood flow is mainly regulated by aeriole, by alteration in their diameter.Increase or decrease the pephenl resistance to blood flow.