This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nervous system, Subject name: Physiology
The first physiological response to high environmental temperature is 
Select and explain. 
A. Sweating, B. Vasodilatation, C. Decreased heat production, D. Non-shivering thermogenesis
B: Vasodilatation
Answer: B: Vasodilatation 
Explanation: Under mechanisms activated by heat cutaneous vasodilation comes first followed by sweating increased respiration, decreased heat production, anorexia, apathy, and ineia. Ref: Ganong&;s review of medical physiology; 23rd edition; pg: 285; Table 18-4.