Radar imaging from the space shuttle Endeavor has provided evidence that the Sahara Desert
A)has always been an arid environment.
B)was once a tropical region,with many different types of vegetation.
C)once had an extensive system of river channels,which are now dry.
D)has sand dunes in excess of 300 m in height.

Question

Quizplus · Accepted Answer

Radar imaging from the space shuttle Endeavor revealed evidence of ancient river channels beneath the Sahara Desert, indicating that it once had an extensive system of rivers that are now dry.

Radar Imaging from the Space Shuttle Endeavor Has Provided Evidence