True or False: Ductility refers to a material's ability to deform under tensile stress.

Ductility is a fundamental property of materials, particularly metals, that describes their ability to undergo significant plastic deformation before rupture or fracture when subjected to tensile stress. This characteristic allows materials to be stretched into wires or shaped into various forms without breaking, making ductility an essential factor in many engineering applications.

When a material is ductile, it can absorb energy and deform without failing, which is crucial for structures and components subjected to tensile forces. High ductility is typically associated with materials like copper, aluminum, and certain alloys, which can be drawn into wires or formed into complex shapes.

The other options address conditions under which ductility can vary, such as temperature and environment, but do not alter the fundamental definition of ductility itself. The concepts of temperature-dependent ductility and environmental effects on material properties are relevant in specific contexts but do not change the core understanding that ductility specifically relates to the ability of a material to deform under tension. Thus, stating that ductility refers to this ability is accurate and aligns with the scientific definition.