What phase of hair growth is characterized by active growth?

The phase of hair growth characterized by active growth is the anagen phase. During this phase, hair follicles are in a state of active division, leading to the rapid elongation of the hair strand. This is the longest phase of the hair growth cycle and can last several years, allowing hair to grow significantly. The anagen phase accounts for the majority of a hair's lifespan, emphasizing its critical role in hair development and overall length.

In contrast, the catagen phase is a transitional stage where hair growth slows and hair follicles begin to shrink. The telogen phase is a resting phase where hair is not actively growing and may eventually shed. The resting option suggests a period where there is no growth, further distinguishing it from the active growth occurring in the anagen phase. Understanding these phases helps clarify the process of hair growth and the biology behind it.