With reference to the work of wind, consider the following statements: 1. Mushroom rocks are commonly found in river valleys. 2. Winds erode the lower section of the rock more than the upper part. 3. Sand dunes are low hill-like structures formed by wind deposition. Which of the statements given above is/are correct?

Correct Option The correct option is (c) 2 and 3 only. Explanation Wind acts as a prominent geomorphic agent in arid and semi-arid regions (deserts). It shapes the landscape through two primary processes: erosion (abrasion and deflation) and deposition (accumulation of transported materials). Statement-wise Analysis - Statement 1 is Incorrect: Mushroom rocks are characteristic landforms found in deserts, not river valleys. They are created by the mechanical weathering and abrasion caused by wind. River valleys are landforms associated with the erosional work of running water. - Statement 2 is Correct: Winds transport sand and dust particles. The concentration of coarser and heavier sand grains is significantly higher near the ground surface. As a result, the abrasive action of the wind is most effective at the base of rock formations. This leads to the lower section of the rock being eroded more than the upper part, creating a structure with a narrow base and a broad top, resembling a mushroom. - Statement 3 is Correct: Sand dunes are depositional landforms. When the wind velocity drops or the wind encounters an obstacle (such as a rock or vegetation), it drops its load of sand. These accumulations form low hill-like structures known as sand dunes. Key Takeaway: Mushroom rocks are products of differential wind erosion (undercutting), while sand dunes are products of wind deposition in desert environments.

With reference to the work of wind,… - NCERT Class 7 Geography MCQ

NCERT Class 7 Geography — Chapter 2: Our Changing Earth

mcqmedium

With reference to the work of wind, consider the following statements:

Mushroom rocks are commonly found in river valleys.
Winds erode the lower section of the rock more than the upper part.
Sand dunes are low hill-like structures formed by wind deposition.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT The Earth Our Habitat · Page 17

Options

A1 and 2 only
B2 only
C2 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (c) 2 and 3 only.

Explanation

Wind acts as a prominent geomorphic agent in arid and semi-arid regions (deserts). It shapes the landscape through two primary processes: erosion (abrasion and deflation) and deposition (accumulation of transported materials).

Statement-wise Analysis

Statement 1 is Incorrect: Mushroom rocks are characteristic landforms found in deserts, not river valleys. They are created by the mechanical weathering and abrasion caused by wind. River valleys are landforms associated with the erosional work of running water.
Statement 2 is Correct: Winds transport sand and dust particles. The concentration of coarser and heavier sand grains is significantly higher near the ground surface. As a result, the abrasive action of the wind is most effective at the base of rock formations. This leads to the lower section of the rock being eroded more than the upper part, creating a structure with a narrow base and a broad top, resembling a mushroom.
Statement 3 is Correct: Sand dunes are depositional landforms. When the wind velocity drops or the wind encounters an obstacle (such as a rock or vegetation), it drops its load of sand. These accumulations form low hill-like structures known as sand dunes.

Key Takeaway: Mushroom rocks are products of differential wind erosion (undercutting), while sand dunes are products of wind deposition in desert environments.

Your note

More from Chapter 2: Our Changing Earth

Consider the following pairs: 1. Angel Falls : South America 2. Niagara Falls : Africa 3. Victoria Falls : North America Which of the pairs given above is/are correctly matched?

medium

As the river enters the plain, it twists and turns forming large bends known as:

easy

What causes the movement of Lithospheric plates?

easy

With reference to Earthquakes, consider the following statements: 1. The place in the crust where the movement starts is called the focus. 2. The place on the surface above the focus is called the focus. 3. Vibrations travel outwards from the epicentre as waves. Which of the statements given above is/are correct?

medium

The material carried by the glacier such as rocks, sand, and silt gets deposited to form:

easy

Keep practising Chapter 2: Our Changing Earth

Work through every question from this NCERT chapter.

Browse all NCERT Class 7 Geography chapters