Randomized Controlled Studies: This is a study in which 1) There are two groups, one treatment group and one control group. The treatment group receives the treatment under investigation, and the control group receives either no treatment (placebo) or standard treatment. 2) Patients are randomly assigned to all groups.
winds that blow in a steady direction can move a dune. such wind will consistently pick up sand from one side and deposit it to a other side. this causes the entire dune to s â¦ lowly move in the direction if the wind.
A hill or ridge of sand piled up by the wind is called a sand dune. Dunes may form wherever there is a lot of loose sand and enough wind to move it. Beaches and deserts are common places for dunes. A sand dune forms when the wind shapes sand grains into a mound or ridge.