: A hair consists of two main parts: the living follicle beneath the skin and the dead shaft above it. The shaft itself has three layers:

: Hair grows in three repeating phases: Anagen (growth, lasting 2–7 years), Catagen (transition), and Telogen (resting/shedding).

: The outer protective "armor" made of overlapping scales .

Hair is a complex biological structure that serves as a powerful medium for self-expression , a marker of cultural identity, and a functional protective barrier for the human body. The Biology of Hair