What are used to support flooring? footing gussets joists purlins

The correct answer is joists.<br /><br />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.<br /><br />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.<br /><br />Therefore, the correct answer is joists, as they are the structural members specifically designed to support flooring in buildings.