Rectangular, vertical panels that provide lateral support to a building are known as what?

The correct answer is shear walls, which are integral structural elements designed to provide lateral support to a building. They are typically made of reinforced concrete or masonry and are strategically placed within the structure to resist lateral forces arising from wind, earthquakes, or other dynamic loads. By doing so, shear walls help maintain the building's stability and integrity during extreme conditions, preventing excessive swaying and potential structural failure.

In comparison, moment connections refer to joints in a frame structure that allow for the transfer of bending moment between connected members, but they do not serve the same function as shear walls in resisting lateral forces. Diagonal bracings are structural elements that help provide stability, but they are typically used in truss systems or frames rather than as standalone walls in vertical structures. Bearing-wall structures focus on load-bearing capabilities but do not specifically address lateral support mechanisms like shear walls do. Thus, shear walls effectively fulfill the role described in the question, distinguishing them as the correct answer.