Which statement characterizes plain arches?

• A. Plain arches have a significant up-thrust and don't have the same 'easy' flow that plain arches do.
• B. Plain arches have an even flow of ridges from one side to the other with no 'significant up thrust'.
• C. Plain arches have two deltas.
• D. Plain arches emerge only on the little finger.

Answer: (B)

Plain arches are defined by a smooth, even ridge flow that enters from one side of the print and exits on the opposite side, with no pronounced upward rise. This lack of a significant upthrust means there is no peak or tent-like shape, which is why plain arches are described as having a uniform, straight-to-curved flow across the print. The statement that describes an even flow from side to side with no significant up thrust captures this characteristic exactly.

If a ridge pattern shows a noticeable upward surge, that points to a tented arch rather than a plain arch, since the upthrust creates that tent-like appearance. Deltas are not part of plain arches (loops and whorls have deltas), so describing plain arches as having two deltas would be inaccurate. And fingerprint patterns aren’t restricted to one finger; they can appear on any digit, so claiming emergence only on the little finger isn’t a defining trait.