Which layer of the skin supplies it with oxygen and nutrients?

The papillary layer is the correct answer as it plays a crucial role in supplying the skin with oxygen and nutrients. Located just beneath the epidermis, the papillary layer consists of loose connective tissue and contains many capillaries. These capillaries provide essential blood flow, delivering oxygen and nutrients to the avascular epidermis above it. This layer is also responsible for the formation of dermal papillae, which enhance the interface between the dermis and epidermis, further promoting the exchange of substances necessary for skin health.

Other layers, such as the stratum corneum, primarily serve as a protective barrier without a blood supply. The reticular layer, while deeper and thicker, primarily provides structural support through dense connective tissue. The basal layer, although vital for the creation of new skin cells, does not directly supply the skin with oxygen and nutrients in the same way that the papillary layer does.