human
What are the different types of sand dunes?
assistant
The main types of sand dunes include linear, transverse, barchan, parabolic, and star dunes. Linear dunes are formed by wind blowing across a flat surface. Transverse dunes are formed when winds blow from one direction to another. Barchan dunes form when winds blow in one direction, creating crescent-shaped hills. Parabolic dunes have curved sides that resemble a parabola. Star dunes are created when strong winds blow parallel to each other, forming a star shape.