Final answer:
The reticular layer of the dermis is responsible for blood vessel formation, which nourishes the skin and supports its functions.
Step-by-step explanation:
The question is asking about the function of the reticular layer of the dermis, specifically in relation to the options provided: blood vessel formation, nutrient absorption, synthesis of hormones, and hair production. The reticular layer underlies the papillary layer and is composed of dense, irregular connective tissue. This layer is known to be well vascularized, having a rich supply of blood vessels (Dermal Circulation), which provide nutrients to dermal cells and the lowest layer of the epidermis, the stratum basale. Given the options and the description provided, the reticular layer is primarily responsible for blood vessel formation, as these vessels play a crucial role in bringing nutrients and oxygen to the skin, which supports numerous functions including repair and growth.