52.The diagram below shows the way in which sand dunes are formed. Summarize the information by selecting and reporting the main features, and make comparisons where relevant

The graphic illustrates how

sand

dunes are created.

Overall

, it is a mainly 3 stage, natural process. It important things in the process are

wind

,

sand

particles

, wet

sand

and dry

ground

. First of all, the

sand

particles

are blown by the

wind

over the dry sandy

ground

and two areas of wet

sand

.

This

is

then

followed by the second diagram in which it can be seen that as

particles

of

sand

continue to be carried by the

wind

along the

ground

, some

particles

start to adhere to the first and the second wet

ground

in separate piles. The

sand

particles

which have been transported by the

wind

, as illustrated in the final diagram, eventually gather en masse over the area of wet

sand

, piling one on top of the other until they form a

sand

dune. The accumulation of so many

sand

particles

is so large that the dunes, once formed, can deflect the

wind

, forcing it up one side of the dune and down the other. As

this

happens,

particles

of

sand

start gathering and piling up in the next area of wet

ground

.