Which choice most accurately reflects the live load that roofs are designed to support?

Roofs are primarily designed to support a variety of live loads, which refer to the temporary loads that a structure is likely to experience, such as people, furniture, and other movable elements. When considering the overall design and engineering of roofs, these live loads tend to be lighter than the dead loads, which include the weight of the roof materials and any permanent fixtures.

Light loads can include activities that involve maintenance personnel or the occasional use of lighter equipment, which aligns with typical residential or commercial building use. Therefore, the correct choice accurately reflects that roofs are intended to support these lighter loads, ensuring safety and structural integrity without overestimating the capacity required for heavier loads, like heavy equipment or significant environmental factors.

While environmental loads, such as snow or wind, can indeed impact roof support requirements, they are classified as environmental or static loads rather than live loads. Therefore, the emphasis on lighter loads within the context of roof design aligns with engineering best practices for maintaining structural safety under typical usage scenarios.