Review of research on the effects of food promotion to children

Questions 37-40
Complete the summary below.
Choose ONE WORD ONLY from the passage for each answer.
Write your answers in boxes 37-40 on your answer sheet.

There are many different types of dunes, two of which are most commonly found

in deserts throughout the world, the linear dune and the 37 dune, some times also known as the crescentic dune. It’s been long known that in some places dunes can even sing and the answer lies in the sand itself. To produce singing
sand in lab, all the sands must have similar 38 . And scientists have
discovered that the size of the sand can affect the 39 of the sound. But
the function of the varnish composed by a mixture of 40 still remains
puzzling.
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