Segments of the oceanic ridge system that are gentler and less rugged in slope due to faster rates of seafloor spreading are called:

Oceanic ridges and rises.

Explanation:

The divergence caused by the movement do the mid-oceanic ridges system and ongoing process of the seafloor spreading takes gentler and ore rugged forms and as a result of this there is a continuous spreading of the seafloor and rising of the ridges takes place and uplifting of the ocean floor due to the convective currents that comes from below.