Context: Figure: Sahara Desert.
The Sahara Desert in northern Africa is the largest hot desert in the world. Less than one-fifth of this desert is covered in sand dunes. Most of the Sahara Desert is covered by bare rock, gravel, and pebbles!
Which statement describes the Sahara Desert ecosystem?
A. It has thick, moist soil
B. It has dry, thin soil.
C. It has only a few types of organisms.
From the given choices, pick the correct answer and respond by indicating the letter of the correct option.

B