What is an erg, and what challenges do they pose for people.

An erg is a desert that has dunes also known as a sand sea. Individual grains of sand are picked up by the wind and bounce along the ground until they begin to accumulate. This often causes ripples, as seen in the photo to the left. Eventually, the sand may begin to build up, forming a large dune.

Explanation:

An erg, also known as a sand sea, is an area in a desert where sand gathers overtime and is blown into landforms called dunes. Some of the ergs and dunes in the Sahara took tens of thousands of years to form, and some are more than 600 feet high. Ergs are hard to cross, so most routes through the Sahara avoid them.

I hope this helps anyone! :)

the first question's answer is a.

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