In thermoregulation, which statement correctly distinguishes eccrine and apocrine glands?

• A. Apocrine glands produce watery sweat for cooling; eccrine produce odor
• B. Eccrine glands produce lipid-rich sweat; apocrine glands watery
• C. Eccrine glands produce clear watery sweat for evaporative cooling; apocrine glands secrete lipid-rich sweat contributing to odor
• D. Both primarily serve cooling; neither produce odor

Answer: (C)

The key idea is that eccrine glands are the main sweat glands for cooling, while apocrine glands produce a different type of sweat that is involved with body odor. Eccrine glands secrete clear, watery sweat rich in water and salts, which evaporates from the skin to remove heat. Apocrine glands, located mainly in areas like the armpits and groin, secrete a lipid- and protein-rich sweat into hair follicles; when bacteria break down these lipids and proteins, odor is produced. So the statement that best fits thermoregulation and odor production is that eccrine sweat is clear and watery for evaporative cooling, whereas apocrine sweat is lipid-rich and contributes to odor.