What type of fingerprint classification involves at least one friction ridge making a complete closed circuit?

The type of fingerprint classification that involves at least one friction ridge making a complete closed circuit is known as a whorl. Whorls are characterized by a circular or spiral pattern where the ridges form at least one complete loop around a central point. This distinct formation is significant in fingerprint analysis because it helps in uniquely identifying individuals due to the complexity and variability of whorl patterns.

In contrast, loops consist of ridges that enter from one side and exit on the same side, forming a continuous flow rather than a closed circuit. Arches are defined by ridges that rise in the center and slope toward both sides without any closed loops. Meanwhile, the term "pattern" is more general and does not refer to a specific classification type. Thus, whorls are specifically categorized due to their closed circuit structure, making them recognizable and important in forensic studies for identification purposes.