Fill in the blank: During a landslide, broken pieces of large and small rocks move downhill due to a force called .
The photograph shows the Erg Chebbi Dunes in the Sahara Desert.
The shape of the land in this desert is always changing.
Which type of erosion forms sand dunes?
The coastline shown in the image has been eroded by the ocean. Would this change occur quickly or over a long period of time?