Consider the following statements about the decomposition in soil: 1. Dead plants and animals in the soil are decomposed exclusively by chemical weathering, not by organisms. 2. Decomposition releases nutrients back into the soil. 3. These nutrients are then absorbed by plants. Which of the statements given above is/are correct?

The correct option is (c) 2 and 3 only. Explanation Decomposition is a vital ecological process where complex organic matter from dead plants and animals is broken down into simpler inorganic substances. This process is primarily driven by biological agents known as decomposers. - Statement 1 is Incorrect: Decomposition is not achieved exclusively by chemical weathering. It is predominantly a biological process carried out by microorganisms such as bacteria and fungi (saprophytes), as well as detritivores like earthworms. Chemical weathering refers to the breakdown of rocks and minerals, not the biological breakdown of organic biomass. - Statement 2 is Correct: The primary function of decomposition is to convert organic matter back into inorganic substances. This process, often called mineralization, releases essential nutrients (such as nitrogen, phosphorus, and potassium) back into the soil pool. - Statement 3 is Correct: Once nutrients are released into the soil in inorganic forms, they become available for uptake by plant roots. Plants absorb these nutrients to synthesize proteins, chlorophyll, and other essential compounds required for growth and development. Key Takeaway: Decomposition is a biological process driven by microorganisms that recycles nutrients from dead organic matter back into the soil, making them available for plant absorption.

Consider the following statements about the decomposition in… - NCERT Class 8 Science MCQ

NCERT Class 8 Science — Chapter 1: Crop production and management

mcqeasy

Consider the following statements about the decomposition in soil:

Dead plants and animals in the soil are decomposed exclusively by chemical weathering, not by organisms.
Decomposition releases nutrients back into the soil.
These nutrients are then absorbed by plants.

Which of the statements given above is/are correct?

NCERT textbook question

From NCERT Science - class 8 · Page 2

Options

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

Did you get this right?

Solution

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

Explanation

Decomposition is a vital ecological process where complex organic matter from dead plants and animals is broken down into simpler inorganic substances. This process is primarily driven by biological agents known as decomposers.

Statement 1 is Incorrect: Decomposition is not achieved exclusively by chemical weathering. It is predominantly a biological process carried out by microorganisms such as bacteria and fungi (saprophytes), as well as detritivores like earthworms. Chemical weathering refers to the breakdown of rocks and minerals, not the biological breakdown of organic biomass.
Statement 2 is Correct: The primary function of decomposition is to convert organic matter back into inorganic substances. This process, often called mineralization, releases essential nutrients (such as nitrogen, phosphorus, and potassium) back into the soil pool.
Statement 3 is Correct: Once nutrients are released into the soil in inorganic forms, they become available for uptake by plant roots. Plants absorb these nutrients to synthesize proteins, chlorophyll, and other essential compounds required for growth and development.

Key Takeaway: Decomposition is a biological process driven by microorganisms that recycles nutrients from dead organic matter back into the soil, making them available for plant absorption.

Your note

More from Chapter 1: Crop production and management

Which one of the following soil nutrients is naturally replenished by the cultivation of leguminous crops?

medium

With reference to 'Harvest Festivals', consider the following statements: 1. They mark the period of harvest and are celebrated with joy. 2. Pongal and Bihu are festivals exclusively celebrated in Western India. 3. These festivals are celebrated in various parts of the country. Which of the statements given above is/are correct?

medium

With reference to weedicides, consider the following statements: 1. They are chemicals used to control weeds. 2. They are sprayed to kill the main crop along with the weeds. 3. They are best sprayed during the vegetative growth of weeds before flowering. Which of the statements given above is/are correct?

medium

Consider the following statements regarding the nutrient content of Manure vs Fertiliser: 1. Manure is richer in plant nutrients like nitrogen and phosphorus compared to fertilisers. 2. Fertilisers are very rich in nitrogen, phosphorus, and potassium. 3. Manure provides humus which fertilisers do not. Which of the statements given above is/are correct?

medium

Which one of the following is an organic soil amendment derived from the decomposition of plant or animal waste?

easy

Keep practising Chapter 1: Crop production and management

Work through every question from this NCERT chapter.

Browse all NCERT Class 8 Science chapters