Final answer:
Sebaceous glands in the skin produce sebum, which lubricates and waterproofs the skin and hair. Sebum also has antibacterial properties that protect against microbial infections and prevent water loss. These glands become more active during puberty due to hormone stimulation.
Step-by-step explanation:
The normal function of sebaceous glands in the skin is to lubricate and waterproof the skin and hair. Sebaceous glands are a type of oil gland found throughout the body, mostly associated with hair follicles. They produce and secrete an oily substance called sebum onto the skin surface. This sebum helps keep the keratinized cells of the stratum corneum hydrated, thereby ensuring skin pliability.
The fatty acids in sebum also exhibit antibacterial properties, which help protect the skin from microbial infections and aid in preventing water loss, especially in low-humidity environments. Hormones, which stimulate sebum production, become more active during puberty, making these glands less active in childhood.