Final answer:
In response to a drop in temperature, the body is expected to undergo vasoconstriction. This conserves heat by reducing blood flow to the skin. Sweating, increased heart rate, and vasodilation occur with an increase in temperature, not a decrease.
Step-by-step explanation:
When a body experiences a drop in temperature, a common response that can be expected is vasoconstriction. This is a physiological response where the blood vessels in the skin constrict to minimize heat loss, thus preserving warmth in the body. The other responses listed, such as sweating, increased heart rate, and vasodilation, are typically associated with a rise in body temperature, not a drop. Sweating is a cooling mechanism, increased heart rate can occur during hyperthermia to increase blood flow and heat dispersion, and vasodilation increases blood flow to the skin's surface to release heat. However, in response to cold, vasoconstriction helps to reduce blood flow to the skin, which conserves body heat and helps prevent further decrease in body temperature. Venoconstriction, a related concept, can increase venous return to the heart, but this is not directly related to thermoregulation.