Why would you expect to find normal microbiota present on your hands even after washing them?

• A. Normal microbiota are only present on unwashed hands and are removed entirely by soap.
• B. Normal microbiota are airborne and only settle on hands after washing.
• C. Hand washing sterilizes the skin, eliminating all microorganisms including normal microbiota.
• D. Normal microbiota are deeply embedded in the skin and are not completely removed by washing.

Answer: (D)

Verified step by step guidance

1. Understand the concept of normal microbiota: these are microorganisms that naturally reside on the skin and other body surfaces without causing harm, often providing protective benefits.
2. Recognize that normal microbiota can be found in different layers of the skin, including deeper layers such as hair follicles and sweat glands, not just on the surface.
3. Consider the effect of hand washing: while washing with soap and water removes many microorganisms from the surface, it does not penetrate deeply enough to remove all normal microbiota embedded in the skin layers.
4. Recall that sterilization is a process that eliminates all microorganisms, but typical hand washing is not sterilization; it reduces microbial load but does not completely eliminate normal microbiota.
5. Conclude that normal microbiota remain present on hands after washing because they are deeply embedded in the skin and are not entirely removed by routine hand washing.