<prompt> The first physiological response to high environmental temperature isSweatingVasodilatationDecreased heat productionNon-shivering thermogenesis  <response>: 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. 