Hair elasticity refers to what characteristic of hair?

Hair elasticity specifically refers to the ability of the hair to stretch and then return to its original length without permanent deformation. This characteristic is crucial as it indicates the hair's health and strength. When hair has good elasticity, it can withstand styling processes like curling or straightening without breaking.

Elasticity is affected by several factors, including the hair’s moisture content, protein structure, and overall health. A well-cared-for strand of hair will stretch and snap back just as a rubber band does, suggesting that the hair can handle the stresses of daily styling and environmental factors.

While other choices may represent different attributes of hair, they do not pertain to how hair behaves under tension, which is the defining factor of elasticity.