Final answer:
When the body is too cool, blood vessels in the skin constrict, sweat production decreases, and blood flow to the skin is reduced, all of which help retain heat and maintain body temperature.
Step-by-step explanation:
When the body is too cool, blood vessels in the skin constrict, or narrow, thus conserving body heat. Additionally, sweat glands stop producing sweat and blood flow to the skin decreases. This helps to retain heat and maintain body temperature.