How does the process that ovcurs at mid-ocean ridges and ocean trenches illustrates the cycling of matter?

This uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary. The other process proposed to contribute to the formation of new oceanic crust at mid-ocean ridges is the "mantle conveyor".

a- all cells come from pre-existing cells

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