Question

In coastal areas, wind moves sand, blowing away or engulfing the soil, and eventually creating sand dunes

Answer 1

Sand dunes are formed by the wind, it is formed usually along the beach or desert. It is formed when the air continues to blow sand into an area behind an object. It continues to grow as grains of sand get condensed. The sand can be transported to a different location by saltation, surface creeps and by suspension where it can settle along with beach and desert in order to form dunes.

Answer 2

In physical geography, a dune is a hill of loose sand built by wind or the flow of water. Dunes occur in different shapes and sizes, formed by interaction with the flow of air or water. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind. The valley or trough between dunes is called a slack. A "dune field" is an area covered by extensive sand dunes. Dunes occur, for example, in some deserts and along some coasts.