The oily mixture that protects against pathogens and waterproofs the skin is produced by

• A. Sebaceous glands
• B. Eccrine glands
• C. Sweat glands
• D. Endocrine glands

Answer: (A)

Sebaceous glands produce an oily sebum that coats the skin and hair. This lipid-rich film helps waterproof the skin and provides a protective barrier against pathogens. Eccrine glands release watery sweat for cooling, not oil. Sweat glands in general aren’t sources of oil, and endocrine glands secrete hormones into the bloodstream, not onto the skin surface. So the oily protective mixture comes from sebaceous glands.