Item WE050001: Wind can gradually wear away the solid rock of river valleys as much as thousands of feet over millions of years.

Which of the following statements describes how wind can change valleys?

  1. Wind can gradually wear away the solid rock of river valleys as much as thousands of feet over millions of years.
  2. Wind can wear away the solid rock of river valleys no more than several feet over many millions of years.
  3. Wind can wear away the solid rock of river valleys no more than several inches over many millions of years.
  4. Wind cannot wear away the solid rock of river valleys, even over many millions of years.

Statistics for this item are available in the Original Project.