Final answer:
The main structures of the skin, beginning with the outermost layer, are the epidermis, dermis, and subcutaneous tissue.
Step-by-step explanation:
The main structures of the skin, beginning with the outermost layer, are the epidermis, dermis, and subcutaneous tissue. The epidermis is the outermost layer of the skin, consisting of epithelial cells. It forms a protective, waterproof layer called the stratum corneum. The dermis is the layer beneath the epidermis and contains most of the skin's structures, including blood vessels, nerve endings, hair follicles, and glands. The subcutaneous tissue is the deepest layer of the skin and acts as insulation and padding.