What is a key characteristic of dunes?

A key characteristic of dunes is that they can change shape and size due to wind. Dunes are formations created by the accumulation of sand, which is primarily shaped by the action of wind. The movement of wind can cause sand to be deposited or eroded, allowing dunes to shift and evolve over time. This dynamic nature of dunes makes them interesting geological features, as their shape and size can vary significantly based on wind direction, speed, and sand supply.

While it is true that certain organisms or conditions can lead to more stability in certain dunes, their ability to change reflects the ongoing influence of environmental factors, particularly wind. This characteristic also sets them apart from more permanent landforms, which do not typically undergo significant changes in shape and size. Dunes may be found in various environments, not just deserts, and they are not solely formed by water flow, but rather by the wind's action on loose sand.