How do oceans ridges and deep-sea trenches support the theory of sea floorr spreading?

how do oceans ridges and deep-sea trenches support the theory of seafloor spreading.How do oceans ridges and deep-sea trenches support the theory of sea floorr spreading?
Mid-oceanic ridges are mountain chains where upwelling lava is extruded onto the seafloor as pillow basalts. This is documented by deep-sea submersibles, and older pillow basalts further away from the spreading center must have a similar origin. Deep-sea trenches are locations where oceanic plates are subducted under continental plates, or under younger oceanic plates. Since spreading centers a creating new oceanic crust, old oceanic crust has to be destroyed, and (deep-sea) trenches are the best (and only) places where this is done.How do oceans ridges and deep-sea trenches support the theory of sea floorr spreading?
Mid-oceanic ridges and deep sea trenches are both results of plate movement, namely DIVERGENT plate movement at a constructive plate boundary, i.e. when two plates move away from each other.





When two oceanic plates move apart, the magma rise through the gap, to the floor and solidify, thus forming new crust and adding on to the ocean floor, allowing the seafloor to spread. Mid-oceanic ridges and deep sea trenches are also formed in the process.