What characterizes an opening in construction?

An opening in construction is characterized by the absence of trim. This is significant because trim is typically used to finish the edges of an opening, providing a clean and aesthetically pleasing appearance; however, not all openings require trim, especially if they are not intended for specific installations like doors or windows.

In practice, openings can exist without any trim and may serve various purposes, such as being a structural element or providing access. This flexibility allows for different design and construction scenarios. The other options do not accurately describe characteristics of openings; for instance, openings don't necessarily require more material, nor do they have to always include a door or be limited to windows. Openings can serve varied functions depending on the design intent and structural requirements.