Which of the following is a function of the skin?

The function of absorption is indeed a key role of the skin. The skin's outer layer, or epidermis, acts as a barrier that allows certain substances to be absorbed into the body while protecting against harmful elements. This includes the absorption of moisture, nutrients, and various topical products applied to the skin. For example, certain skincare products are formulated to penetrate the skin's surface, delivering beneficial ingredients directly to the deeper layers, aiding in hydration and overall skin health.

Other options, while related to bodily functions, do not accurately describe the primary roles of the skin itself. Hormones are primarily secreted by glands such as the adrenal glands and thyroid, rather than by the skin. Blood cell production primarily occurs in the bone marrow, and while the skin does have a vascular system, its main functions do not typically involve the direct regulation of vascular health but rather the maintenance of homeostasis and protection. Therefore, absorption is the most accurate answer regarding the skin's functions.