Which feature forms as a result of a tectonic plate boundary that creates an underwater miuntainbrange in the open ocean?

Mid-ocean ridge. A mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.

The answer is mid-ocean ridge

Explanation:

This geographical feature is found in divergent boundaries where tectonic plates are moving away from each other. The magma from mantle rises (upwells) to replace the void. Therefore, as magma rises and accumulates, as it cools into new crust, it forms mountain ranges along the boundary.