Answer:
Erosion and weathering
Step-by-step explanation:
First what is erosion and weathering?
Erosion-Resources worn away and transported by natural forces from one place to another.
Weathering-Being worn away by long exposure to the atmosphere.
Now that we know that, what does this have anything to do with it?
Metamorphic and igneous rocks are weathered and eroded down till they turn into Sediment , after they turn into Sediment, they will be compressed and form sedimentary rocks over time and start the rock cycle again.