Final answer:
Thick folds of skin with sebaceous glands refer to areas with hair, excluding palms and soles, where these glands secrete sebum for hair and skin protection, found in the dermis.
Step-by-step explanation:
The thick folds of skin lined with sweat and sebaceous glands are typically found in regions where the skin has hair, except palms of the hands and soles of the feet. Sebaceous glands are types of exocrine glands that secrete sebum, a lubricating substance that helps to waterproof the hair and skin, preventing them from drying out. The sebum also possesses antibacterial properties to protect the skin from microbes.
The dermis located just beneath the epidermis - which is the outermost skin layer - is responsible for containing these glands along with hair follicles, blood vessels, and other structures essential for skin health. Sweat glands, on the other hand, are tubular structures that produce sweat to help regulate body temperature.