What term refers to the hair's ability to stretch and then return to its original form without breaking?

The term that refers to the hair's ability to stretch and then return to its original form without breaking is elasticity. Elasticity is a crucial characteristic of hair because it indicates the hair's strength and ability to withstand tension without suffering damage. When hair has good elasticity, it can be manipulated through styling techniques such as curling or straightening, and still maintain its integrity.

In contrast, while strength relates to how much force hair can endure before breaking, it does not capture the component of returning to its original shape. Softness pertains to the texture and feel of hair rather than its structural capabilities, and texture itself describes the surface characteristics of hair, which is different from how it reacts to stress and movement. Thus, elasticity is the most accurate term in this context for the described quality of hair.