What process is described by the term "ridge push"?

Ridge push refers specifically to the tectonic process that occurs at mid-ocean ridges, where new oceanic crust is formed by upwelling magma. As magma rises and solidifies, it creates young, hot, and less dense rock, which is elevated compared to the surrounding older, cooler oceanic crust. This topographic elevation results in a gravitational force that pushes the older plates away from the ridge and causes them to move laterally.

Choosing the answer related to the expansion of rocks at mid-ocean ridges accurately aligns with this definition, as this process initiates the ridge push mechanism. Additionally, the term captures the essence of how the geological activity at these ridges contributes to plate tectonics through the formation and movement of the crust.