With reference to biological activity and weathering, consider the following statements: 1. Burrowing by organisms helps in exposing new surfaces to chemical attack. 2. Decaying plant matter prevents the production of humic acids. 3. Plant roots exert no mechanical pressure on earth materials. Which of the statements given above is/are correct?

The correct option is 1 only Explanation Biological weathering involves the contribution of living organisms-such as plants, animals, and microorganisms-to the disintegration (mechanical) and decomposition (chemical) of rock materials. It acts as a bridge between physical and chemical weathering processes. Statement-wise Analysis - Statement 1 is Correct: Burrowing and wedging by organisms such as earthworms, termites, and rodents loosen the soil and rock material. This activity facilitates the penetration of moisture and air into the subsurface and exposes new surfaces to chemical attack, thereby accelerating weathering. - Statement 2 is Incorrect: Decaying plant and animal matter leads to the production of humic, carbonic, and other organic acids. These acids do not prevent but rather enhance the decay and solubility of minerals in the rock, promoting chemical weathering. - Statement 3 is Incorrect: Plant roots growing into cracks and crevices of rocks exert tremendous mechanical pressure on the surrounding earth materials. This pressure widens the cracks and mechanically breaks the rocks apart, a process often referred to as root wedging. Key Takeaway Biological weathering encompasses both mechanical disruption (e.g., root pressure, burrowing) and chemical decomposition (e.g., release of organic acids and humic acids) of geological materials.

With reference to biological activity… - NCERT Class 11 Geography MCQ

NCERT Class 11 Geography — Chapter 4: Geomorphic Processes

mcqeasy

With reference to biological activity and weathering, consider the following statements:

Burrowing by organisms helps in exposing new surfaces to chemical attack.
Decaying plant matter prevents the production of humic acids.
Plant roots exert no mechanical pressure on earth materials.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Fundamentals of Physical Geography · Page 41

Options

A1 and 3 only
B1, 2 and 3
C1 only
D2 only

Did you get this right?

Solution

The correct option is

1 only

Explanation

Biological weathering involves the contribution of living organisms-such as plants, animals, and microorganisms-to the disintegration (mechanical) and decomposition (chemical) of rock materials. It acts as a bridge between physical and chemical weathering processes.

Statement-wise Analysis

Statement 1 is Correct: Burrowing and wedging by organisms such as earthworms, termites, and rodents loosen the soil and rock material. This activity facilitates the penetration of moisture and air into the subsurface and exposes new surfaces to chemical attack, thereby accelerating weathering.
Statement 2 is Incorrect: Decaying plant and animal matter leads to the production of humic, carbonic, and other organic acids. These acids do not prevent but rather enhance the decay and solubility of minerals in the rock, promoting chemical weathering.
Statement 3 is Incorrect: Plant roots growing into cracks and crevices of rocks exert tremendous mechanical pressure on the surrounding earth materials. This pressure widens the cracks and mechanically breaks the rocks apart, a process often referred to as root wedging.

Key Takeaway

Biological weathering encompasses both mechanical disruption (e.g., root pressure, burrowing) and chemical decomposition (e.g., release of organic acids and humic acids) of geological materials.

Your note

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