<unk> s are<unk> s that are associated with the<unk>  and serve a particular function. In humans some of the more common<unk> s are hairs (sensation, heat loss, filter for breathing, protection), arrector pilli (smooth muscles that pull hairs straight), sebaceous glands (secrete sebum onto hair follicle to oil the hair), sweat glands (can be sweat secreted with strong odour (apocrine) or with a faint odour (eccrine)) and nails (protection).
It is derived from the<unk> , and is usually adjacent to it.
p63 is involved in development.
Skin appendage
Tissue 
Hair
Wound
Sex organ
Human skeleton
Tooth enamel
Bone island