Which of the following is the medium that creates sand dunes?

a. water

b. wind

c. ice

d. gravity

The medium that creates sand dunes are the flow of water or wind. but most of the time is due to wind, that is why sand dunes are created. sand dunes has also purpose, which is to protect the coastal area of from the sea storm or big waves. sand dunes also form when water flows to the sand or gravel