Final answer:
The theory of Plate Tectonics explains how new oceanic crust forms at ocean ridges, moves away, and is destroyed at subduction zones marked by deep-sea trenches.
Step-by-step explanation:
The theory that explains the process of formation, movement, and destruction of oceanic crust at various geological features like ocean ridges and deep-sea trenches is Plate Tectonics. The concept of plate tectonics indicates that the Earth's lithosphere is divided into multiple tectonic plates that are constantly moving due to mantle convection. As tectonic plates diverge at ocean ridges, new oceanic crust is formed by the upwelling of mantle material that solidifies into basaltic rock.
This crust gradually moves away from the ridges, driven by the convection in the mantle. Eventually, older oceanic crust is subducted back into the mantle at subduction zones marked by deep-sea trenches, where it is remelted and recycled into the mantle. This cycle of creation and destruction balances the crust on Earth's surface.