Why do you find smooth rounded rocks at the seashore and in rivers?

Smooth rounded rocks are found at the seashore and in rivers due to the natural process of erosion and weathering. As water flows over rocks, it gradually wears away sharp edges and rough surfaces, resulting in a smoother appearance. This process is enhanced by the constant movement of water, which transports and tumbles the rocks, further rounding them over time. Ultimately, the combination of abrasion and hydraulic action leads to the characteristic smoothness of these stones.