Why the pebble on the beach were round and smooth?

Pebbles on the beach are round and smooth due to the natural processes of erosion and weathering. As they are carried by water currents and waves, they collide with other rocks and sediment, gradually wearing down their jagged edges. This continuous tumbling and abrasion refine their shape, resulting in the rounded, polished appearance characteristic of beach pebbles. The process can take thousands of years, contributing to the smoothness and uniformity of these stones.