Answer: C. sweat glands
Step-by-step explanation:
Sweat glands are small structures of the skin that produce sweat, which is mostly water. This glands are a type of exocrine gland, which produces and secretes this substance by way of a duct. They are controlled by the sympathetic nervous system, and their main function is to regulate body temperature. When the internal temperature rises, the sweat glands secrete water to the skin surface. Then, the heat is removed by evaporation, and that helps to lower the body temperature.