How does sea floor spreading provide an explanation for how continents may move over earths surface? (i know this isn't physics, but there was no earth science option)

Alfred Wegner first proposed the idea that all the seven continents were once one super continent called "Pangea". Everyone considered his idea as a joke until he proved his theory with evidence of matching fossils, matching mountain ranges, and how all the continents fit together like puzzle pieces. Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics.