Which statement best describes the role of the integumentary system in infection protection?

• A. It regulates body temperature.
• B. It enables gas exchange.
• C. It prevents pathogens from entering the body.
• D. It stores minerals.

Answer: (C)

The main idea is that the skin acts as a protective barrier against infection. The outer skin layer, the epidermis, is made of tough, keratin-rich cells with tight junctions that form a physical shield, making it hard for pathogens to penetrate. Sweat and sebum on the surface create an acidic, antimicrobial environment—sweat contains substances like lysozyme, and sebaceous secretions help deter microbes. The skin also constantly sheds dead cells, which helps remove attached microbes, and it houses immune cells such as Langerhans cells that detect invaders and alert the body’s defenses. Because these factors collectively prevent pathogens from entering the body, this statement best describes the integumentary system’s role in infection protection.