Which structure grows deeper into the dermis in search of blood supply during active growth stages?

The correct answer, indicating that the follicle grows deeper into the dermis in search of blood supply during active growth stages, is based on the anatomical and physiological relationship between hair follicles and the skin layers.

During hair growth, the follicle is the structure that houses the hair root and extends down into the dermis. The follicle is crucial for supplying the hair with necessary nutrients and oxygen, which it obtains through a network of blood vessels in the dermis. As the hair grows, the follicle must often adapt and grow deeper into the dermal layer to ensure a consistent and adequate blood supply, especially during the anagen phase, which is the active growth stage.

The hair shaft, on the other hand, is the visible part of the hair that extends above the skin, but it does not reach deeper into the dermis; rather, it is formed from the hair bulb found at the base of the follicle. The hair bulb plays a vital role in generating the hair and is located at the deepest part of the follicle, yet it is the follicle itself that extends into the dermis. The epidermis is the outermost layer of the skin and does not grow into the dermis; it provides a protective barrier but