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.
What are the conditions necessary for the formation of sand dunes? Hi, Dunes are formed by interaction with the wind. Wind speeds of 10 to 20 mph,. are necessary for sand to start saltating under the direct pressure of the wind.