What are used to support flooring? footing gussets joists purlins

The correct answer is joists.Joists are horizontal structural members used to support flooring in buildings. They are typically made of wood, steel, or concrete and are spaced at regular intervals to provide a stable and even surface for the flooring material, such as wood planks or concrete slabs.Footings are used to distribute the load of a structure to the ground, providing a stable foundation. Gussets are triangular plates used to reinforce joints or connections between structural members. Purlins are horizontal structural members used to support the roof deck in a roof truss system.Therefore, the correct answer is joists, as they are the structural members specifically designed to support flooring in buildings.