Final answer:
The hair papilla is a small connective tissue that contains nerve endings and blood vessels, and it's situated at the base of the hair follicle.
Step-by-step explanation:
The correct answer to the question is D) Hair papilla. The hair papilla is a small connective tissue peg that contains nerve endings and blood vessels, and it is located at the base of the hair follicle. This structure is essential for the growth of the hair as it provides the nutrients and signals necessary for hair development. It is surrounded by the hair bulb, which is the structure at the base of the hair root. The hair matrix, which is a layer of basal cells, is also located in this region and is responsible for producing the actual strand of hair.
The hair bulb also contains the aforementioned hair matrix, while the hair follicle is the cavity that the hair grows from. Additionally, the hair shaft is the part of the hair that extends above the skin's surface, while the hair cuticle is the outermost layer of the hair strand which protects it.
The hair papilla is a small connective tissue peg that contains nerve endings and blood vessels. It is located at the base of the hair follicle and is responsible for supplying nutrients to the growing hair.