Which term refers to the ability of hair to stretch and return to its normal state?

The term that refers to the ability of hair to stretch and return to its normal state is elasticity. Elasticity in hair is a critical property because it indicates the hair's health and strength. Hair that has good elasticity can withstand styling and manipulation without breaking. When hair is stretched, it should have the ability to return to its original length and shape, which signifies that the protein structure of the hair is intact and functioning properly. This property is essential for maintaining the overall integrity and appearance of the hair, especially when using chemical treatments, heat styling, or during physical manipulation.

In contrast, terms like fade, drab, and double process do not pertain to the physical properties of hair. Fade typically refers to the gradual loss of color in hair dye, drab may describe muted or dull hair tones, and double process relates to a coloring technique that involves two steps for achieving desired hair color. Thus, understanding elasticity is vital for anyone involved in hairdressing, as it helps maintain the quality and longevity of hair styles and treatments.