Which deep valley may develop when a waterfall retreats backward?
Answer and explanation
Correct answer: Gorge
The governing concept is headward erosion. A waterfall retreats upstream when erosion undercuts its hard cap or plunge-pool area; continued retreat leaves behind a long, narrow and very deep valley with steep sides, called a gorge. Hence, option D is correct. An alluvial fan and loess are depositional features, while a beach is formed by coastal sediment accumulation, not retreating river waterfalls.
Frequently asked questions
What is the correct answer to this question?
Gorge
Why is this the correct answer?
The governing concept is headward erosion. A waterfall retreats upstream when erosion undercuts its hard cap or plunge-pool area; continued retreat leaves behind a long, narrow and very deep valley with steep sides, called a gorge. Hence, option D is correct. An alluvial fan and loess are depositional features, while a beach is formed by coastal sediment accumulation, not retreating river waterfalls.
Which subject and chapter does this question cover?
This is a Class 11 Accountancy question. Chapter: Introduction to Accounting.
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