What is subflooring and why is it important in the construction of a building?

Subflooring is a structural layer of material installed under the finished flooring of a building. It provides a stable and level surface for the flooring to be installed on, helps distribute weight evenly, and adds strength to the overall structure of the building. Subflooring is important in construction because it helps prevent sagging, squeaking, and damage to the finished flooring, while also providing a solid foundation for the building's structure.