Which of the following is a characteristic feature of elastomers?

Elastomers are a category of polymers that are characterized by their significant elasticity and flexibility. This unique property allows them to be stretched to considerable lengths and return to their original shape when the stress is released, which is essential in many applications such as seals, gaskets, and various flexible components.

The high elasticity is a result of the molecular structure of elastomers, which includes long, coiled polymer chains that can easily deform and then revert to their original configuration upon the release of stress. This intrinsic property makes elastomers particularly useful in products that require durability and resilience against deformation.

While other characteristics might be present in elastomers, such as low density or thermal resistance, they do not define elastomers as thoroughly as their high elasticity and flexibility do. Therefore, highlighting high elasticity and flexibility as the essential features correctly identifies the core attributes of elastomers, distinguishing them from other materials.