Linked from
The 18 pages that link to Hair, each with the reason it gives.
MammalRelated: Hair is a hallmark mammalian trait, even in species with sparse or modified coats.
Sebaceous glandRelated: Sebum commonly coats hair as it travels up the follicle.
Rhinoceros hornRelated: Rhinoceros horn resembles densely packed hair filaments rather than bone.
Human skinRelated: It is an appendage of skin that contributes to protection and sensation.
HairbrushRelated: Hair’s length, texture, and condition affect how a brush moves through it.