Which fingerprint pattern is characterized by ridges that enter from one side and exit out the other without making a complete circuit?

The fingerprint pattern characterized by ridges that enter from one side and exit out the other without making a complete circuit is the loop. Loops are distinguished by their unique structure where the ridges curve around in a way that forms a definitive entrance and exit. This pattern can be further categorized into radial loops, which open toward the thumb, and ulnar loops, which open toward the little finger.

In contrast, the whorl pattern forms a circular shape where ridges make complete circuits. This means that while they can have various concentric circles, they don't simply enter and exit like in a loop. The arch pattern, on the other hand, features ridges that rise in the center and do not have both an entry and exit in the same way that loops do. Arch patterns generally do not have any significant upthrust and flow smoothly from one side to the other.

Therefore, the defining characteristic of loops, with ridges entering from one side and exiting on the other, directly aligns with the attributes of the correct answer.