Which of the following is a characteristic of flowable composites?

Flowable composites are a specific type of dental restorative material characterized by their low viscosity, which allows them to adapt well to various cavity shapes and sizes. This property makes them especially beneficial in situations requiring minimal preparation, such as in the case of small to medium cavities or areas with limited access. Their ability to flow enables them to fill in microscopic gaps and provide a good seal, which is critical for the longevity of a restoration.

The other options do not accurately describe the characteristics of flowable composites. For instance, while flowable composites can be shaped to some extent, they are particularly favored for their ability to conform to the cavity preparation. They are not limited to temporary restoratives; they can also be used for permanent restorations in certain cases. Additionally, flowable composites do not require mixing with a catalyst to set; they typically cure via light activation, chemical activation, or dual-cure mechanisms, depending on the specific material being used.