Weathering and erosion break up existing rock and produce sediment. Regional metamorphism occurs where tectonic processes cause rocks from the surface to be buried very deeply. Because the Earth is dynamic, environments change through time. If erosion and weathering stopped, the environment wouldn't be able to change through time. Like how it creates oil and such, it would soon run out due to the lack of change.
-Mabel <3
(If you don't mind, please give brainliest! <3)
