Final answer:
Sebum is the complex secretion full of fatty substances produced by sebaceous glands to waterproof and lubricate skin and hair, and also to inhibit microbial growth.
Step-by-step explanation:
The complex secretion containing a high percentage of fatty, oily substances is known as sebum. Sebum is produced by sebaceous glands, which are exocrine glands located in the dermis layer of the skin. These glands produce sebum that is secreted into the hair follicles and eventually makes its way to the skin surface. The primary role of sebum is to waterproof and lubricate the skin and hair. In addition, sebum contains antibacterial properties which help inhibit the growth of microorganisms on the skin. Sebaceous glands are found nearly all over the body, except for the palms of the hands and soles of the feet.