Final answer:
Vasoconstriction is the process that causes people's noses and ears to turn red on cold winter days. This response helps to conserve heat and protect the body from the effects of cold air.
Step-by-step explanation:
On cold winter days, people's noses and ears turn red due to a process called vasoconstriction. This is when the blood vessels in the skin narrow in response to the cold temperature. Vasoconstriction helps to conserve heat by reducing blood flow to the extremities, such as the nose and ears, and directing it to the vital organs.
In addition to conserving heat, vasoconstriction also helps to protect the body from the effects of cold air. By reducing blood flow to the skin's surface, vasoconstriction helps to prevent heat loss and maintain a stable core body temperature.
Overall, the advantage of the body's response to cold is to maintain homeostasis, or a stable internal environment, by conserving heat and protecting the vital organs.