The nail root and the nail body attach to the

What type of burn appears white or black with no immediate pain?

Exposure to ultraviolet light causes the skin to darken by stimulating the

Exposure to ultraviolet light causes the skin to darken by stimulating the

The length of hair is determined by the

This is the dermal layer closest to the epidermis.

Skin color is the result of the

Skin color is the result of the

The central axis of the hair is the

The central axis of the hair is the