In response to a drop in body temperature, what might the nervous system trigger?

When the body experiences a drop in temperature, the nervous system activates mechanisms to conserve heat and raise the body's temperature back to a normal level. One of the primary responses is the contraction of small muscles, which leads to shivering. Shivering is an involuntary response that generates heat through rapid muscle contractions. This helps to increase body temperature by producing heat as a byproduct of muscle activity.

Additionally, while other options might relate to temperature regulation, they do not align with the body's response to cold. Increased sweat gland activity would be associated with the body's response to overheating, not cooling. Vasodilation, which is the widening of blood vessels, occurs in response to heat to increase blood flow to the skin, promoting heat loss instead. Expansion of dermal blood vessels also facilitates heat loss, rather than conserving it. Thus, the contraction of small muscles to induce shivering is the most appropriate response to a drop in body temperature, serving the purpose of generating heat to restore normal body temperature levels.