What are the main layers of the skin?

The correct answer identifies the main layers of the skin as the epidermis, dermis, and hypodermis. The epidermis is the outermost layer, serving as a protective barrier and containing cells like keratinocytes, which produce keratin, an essential protein for skin structure. Beneath the epidermis lies the dermis, which provides strength and elasticity due to its collagen and elastin fibers. It also houses important structures such as blood vessels, nerves, hair follicles, and sweat glands. The hypodermis, or subcutaneous layer, lies beneath the dermis and consists of adipose tissue that helps insulate the body and absorb shock.

In contrast, the other options include incorrect terminology or do not accurately represent the distinct layers of the skin. Specifically, the term "epidermal layer" is redundant since the epidermis is already a distinct layer, and "subcutaneous layer" is not consistently used in dermatological contexts as a main layer but rather describes the tissue beneath the dermis. The inclusion of "epithelial layer" is misleading because it does not represent a specific layer of the skin structure but refers to types of tissue that line surfaces throughout the body. Thus, the option that clearly and correctly outlines