Final answer:
The greatest amount of vasomotor nerve fibers is received by the skin (A). This allows the body, through the sympathetic nervous system, to regulate temperature by controlling blood flow to the skin for heat loss or retention.
Step-by-step explanation:
The question asks which region of the body receives the greatest amount of vasomotor nerve fibers. The correct answer is A) Skin. The vasomotor nerves are part of the sympathetic nervous system that controls the constriction and dilation of blood vessels. During exercise, there is selective vasodilation in several parts of the body, but there is simultaneous vasoconstriction in the vessels leading to the kidneys and most of the digestive and reproductive organs. The skin receives a significant supply of vasomotor nerve fibers, which allows the body to regulate temperature through processes like vasodilation, where blood flow increases to the skin to release heat, or vasoconstriction, where blood flow decreases to retain heat.
The body's 'thermostat' is located in the hypothalamus, which plays a central role in regulating body temperature through various mechanisms, including modulation of blood flow to the skin. Blood flow to the brain remains largely unchanged during situations like exercise because the vessels in the brain do not typically respond to these regulatory stimuli, as they often lack the receptors for such regulation.