Which of the following practices best exemplifies resource conservation in sustainable building?

Using recycled or reclaimed building materials is the practice that most directly conserves resources because it avoids the need to mine, cut, or process new raw materials, thereby cutting energy use and waste. By choosing materials that have already been manufactured, a building reduces its embodied carbon and the demand on finite resources. For example, a new office can use reclaimed timber for flooring and recycled steel for structural framing, which saves the energy and emissions that would have been required to produce fresh timber and steel. This approach keeps materials in use longer and lowers the overall environmental footprint of the construction.