Assertion: desert's sand dune | /r/HasProperty | erg
Facets:
Source sentences:
text: Vegetation is rare, and this ecoregion consists mostly of sand dunes (erg, chech, raoui), stone plateaus (hamadas), gravel plains (reg), dry valleys (wadis), and salt flats.
text: The surface of the desert ranges from large areas of sand dunes (erg), to stone plateaus (hamadas), gravel plains (reg), dry valleys (wadis), and salt flats.