Read the following passage carefully and answer the given questions.
The earthworm is referred to as the farmer's friend. This is because they help in the breakdown of complex organic matter as well as in loosening of soil. Similarly, decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients and the process is called decomposition. Dead plant remains such as leaves, bark, flowers and dead remains of animals, including fecal matter, constitute detritus, which is the raw material for decomposition. Some of the steps in the process of decomposition are fragmentation, catabolism, leaching, humification etc.
The process of decomposition largely requires -
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Oxygen
Option (1) Carbon monoxide — Incorrect. Carbon monoxide is a poisonous gas given out when fuel burns in too little air. Decomposers do not use it for breaking down detritus.
Option (2) Oxygen — Correct. Bacteria and fungi break down detritus by aerobic respiration, so they need oxygen. That is why decomposition slows down where there is no oxygen, as in waterlogged soil, and organic matter then builds up.
Option (3) Nitrogen — Incorrect. Detritus rich in nitrogen does decompose quickly. But that nitrogen is a part of the detritus itself, which affects the rate. It is not a gas that the process uses.
Option (4) Sulphur dioxide — Incorrect. Sulphur dioxide is a polluting gas from burning coal and oil. It harms living things and plays no part in decomposition.
Note: This passage is taken from NCERT as it is. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
NCERT Extract:
Decomposition – …
