The nurse is aware that normal flora that does not cause disease but does prevent disease-causing microorganisms from reproducing is known as:

A) sebum.
B) the epidermis.
C) resident bacteria.
D) the dermis.

Bacteria reside on the skin's outer surface.Resident bacteria constitute normal flora that does not cause disease but does prevent disease-causing microorganisms from reproducing.Sebum,secreted from hair follicles from sebaceous glands,provides an acidic coating.This acid coating protects the epidermis against penetration from chemicals and microorganisms.It also minimizes loss of water and plasma proteins.It is not alive,however,and is not considered flora.The epidermis,or outer skin layer,is the first line of defense from external injury and infection.It contains several thin layers of cells undergoing different stages of maturation.Resident bacteria live on its surface and protect it.Three primary layers make up the skin: the epidermis,the dermis,and subcutaneous tissue.The dermis lies underneath the epidermis and is not considered "flora."