What are the four stages of hair growth?

The four stages of hair growth are anagen, catagen, telogen, and exogen.

During the anagen phase, which is the active growth stage, hair follicles produce new hair cells, resulting in hair growth. This phase can last for several years, determining the length of the hair. The catagen phase is a transitional period where hair growth slows and the hair follicle shrinks. This phase typically lasts a few weeks.

The telogen phase is the resting stage of the hair cycle, where the hair does not grow but remains attached to the follicle. After this phase, hair eventually sheds, which can lead into the exogen phase, where the old hair comes out, making way for new growth to begin again in the anagen phase.

The other options include terms that do not correctly reflect the established stages of hair growth, illustrating a misunderstanding or mislabeling of the biological processes involved. Thus, the correct selection accurately represents the widely recognized stages in hair biology.