What does "rigidity" refer to in terms of physical properties?

Rigidity in terms of physical properties refers specifically to the inability of a material to bend or be shaped when a force is applied. A rigid material maintains its shape and does not deform easily under stress. This characteristic is crucial in various applications where structural integrity is required, such as in construction materials, mechanical components, and even in the human body concerning bone structure.

The understanding of rigidity is essential for distinguishing materials based on their behavior under load. For instance, materials that exhibit high rigidity can be advantageous in certain engineering contexts, as they can support more weight without deforming, while their flexible counterparts may be more suitable for applications requiring some degree of movement or adaptation.

The other options relate to physical properties but do not accurately define rigidity. Flexibility, in contrast, denotes the ability to bend, while hardness refers to a material's resistance to being indented or scratched, and temperature resistance pertains to how well a material can withstand high or low temperatures without degrading. Hence, the concept of rigidity is specifically tied to the inability to change shape or form when force is applied.