Read the given passage and answer the questions that follow:
The earthworm is often referred to as the farmer's 'friend' due to its beneficial role in the breakdown of complex organic matter and soil aeration. Similarly, decomposers play a crucial role in converting complex organic matter into inorganic substances like carbon dioxide, water, and nutrients through the process of decomposition. Detritus, consisting of dead plant remains (leaves, bark, flowers) and animal waste, serves as the raw material for decomposition. Decomposition involves several important steps: fragmentation, leaching, catabolism, humification, and mineralization.
Choose the correct statements about decomposition from the following:
A. All the steps in decomposition operate one after the other on the detritus.
B. Humification and mineralisation occur during decomposition in the soil.
C. Temperature and soil moisture regulate decomposition through their effects on the activities of soil microbes.
D. Bacterial and fungal enzymes degrade detritus into simpler organic substances.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → B and C only
The steps of decomposition do not wait for one another; they work on the detritus together. The work is done by soil microbes, so the climate around them sets the pace.
A. All the steps in decomposition operate one after the other on the detritus. — False. All the steps operate simultaneously on the detritus.
B. Humification and mineralisation occur during decomposition in the soil. — True. Both take place in the soil during decomposition.
C. Temperature and soil moisture regulate decomposition through their effects on the activities of soil microbes. — True. They are the most important climatic factors in decomposition.
D. Bacterial and fungal enzymes degrade detritus into simpler organic substances. — False. In catabolism the enzymes degrade detritus into simpler inorganic substances.
So only B and C are correct.
NCERT Extract:
Decomposition – “… Bacterial and fungal enzymes degrade detritus into simpler inorganic substances. This process is called as catabolism. It is important to note that all the above steps in decomposition operate simultaneously on the detritus (Figure 12.1). Humification and mineralisation occur during decomposition in the soil.”
Decomposition – “… Temperature and soil moisture are the most important climatic factors that regulate decomposition through their effects on the activities of soil microbes.”