People swim in the water or surf on the waves. The beach is pleasant for a stroll. The sand in the sea comes from the land. Soil contains sand. As it erodes, the sand ends up in the sea.
Sand grains are very stable.
They form a system. Learn the parts of this system. Cusps form under certain wind conditions. The diagram shows how soil is made and sand. Every kind of rock weathers slowly by breaking apart into different substances.