Gabriela is studying a map showing rivers flowing through a mountainous region. She notices that the V-shaped river valleys are often much wider than the rivers themselves. Which of the following statements best explains her observation?

W) The rivers carried more water in the past

X) The valleys were formed by glaciers and were later replaced by rivers

Y) A series of cut-banks and point-bars formed as the rivers developed, widening the valley

Z) Mass wasting and stream erosion have widened the valley
Z) MASS WASTING AND STREAM Erosion HAVE WIDENED THE VALLEY