The world's desert regions _____.
a. have always had arid climates
b. are 99 percent covered by active sand dunes
c. are fragile environments
d. have no vegetation
e. have no topographic relief
Question 2
Wind-blown dust-sized particles of silt and clay can settle out to form thick blankets of sediment called _____ that may cover or bury the existing topography over widespread areas.
a. barchans
b. seif
c. deflation hollows
d. loess
e. clay pan