Answer:
The theory of seafloor spreading explains how new crust is created at mid-ocean ridges.
Step-by-step explanation:
This theory proposes that the Earth's crust is made up of tectonic plates that move and spread apart from each other, allowing molten material from the mantle to rise up and fill the gap, forming new crust. This process of plate tectonics also explains the formation of mountain ranges, volcanoes, and earthquakes.