What type of oceanic feature is most likely to cause seafloor spreading?

Oceanic ridges are vital features in understanding seafloor spreading. These underwater mountain ranges are created by tectonic plate movements, specifically at divergent boundaries where two plates move away from each other. As the plates separate, magma from the mantle rises to fill the gap, cooling and forming new oceanic crust. This process continuously adds material to the seafloor, causing it to spread outward from the ridge.

In contrast, deep-ocean basins are depositional areas that form between ocean ridges and continental margins, while deep-ocean trenches are formed at convergent boundaries where one plate subducts beneath another, leading to erosion rather than creation of new crust. Abyssal plains represent the extended flat areas of the ocean floor that result from sediment deposition and do not play a direct role in the process of seafloor spreading. Thus, the characteristics and function of oceanic ridges make them the correct answer in the context of seafloor spreading.