Erosion Breakdown and transport of rocks by atmospheric effects. Flash floods carving out stream beds. Wind eroding rocks. Water carrying sediment and depositing it in river deltas Glaciers carving valleys and depositing rocks. Of course, need an atmosphere to do this need larger planets.
Larger planets have stronger gravity, so can hold on to their atmosphere better so more erosion.
Mercury and the Moon have virtually no erosion, Mars still has a little but at one time had quite a lot going on.