The fibrous protein core formed by elongated cells that contains melanin pigment is the:

A physical side bond that is easily broken by water and heat is a:

The thickness or diameter of the individual hair strand is referred to as hair:

Rays with long wavelengths that penetrate more deeply and produce more heat than visible light are:

A measurement of how much electricity is being used in 1 second is a(n):

Eumelanin provides natural colors ranging from red and ginger to yellow and blond tones.

The medulla, the innermost layer of the hair, is composed of cells that are:

Ultraviolet A light has the longest wavelength of the UV light spectrum.

UV prompts the skin to produce vitamin D, a fat-soluble vitamin that promotes mineralization of bones.

The path of an electric current from the generating source back to the original source is a(n):