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 breaking down of detritus into smaller particles is called:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Fragmentation
Decomposition is the breakdown of detritus (dead plant and animal matter) into simple inorganic substances. It takes place in steps: fragmentation, leaching, catabolism, humification and mineralisation. The first step is fragmentation.
Option (1) Leaching — Incorrect. In leaching, water-soluble inorganic nutrients go down into the soil and settle as unavailable salts. It moves nutrients; it does not break detritus into pieces.
Option (2) Catabolism — Incorrect. In catabolism, the enzymes of bacteria and fungi degrade detritus into simpler inorganic substances. It is a chemical breakdown, not a breaking into smaller particles.
Option (3) Fragmentation — Correct. Breaking detritus into smaller particles is fragmentation. The small pieces have a much larger surface, so bacteria and fungi can then act on them faster.
Option (4) Mineralisation — Incorrect. In mineralisation, humus is broken down further by microbes to release inorganic nutrients. It is the last step, not the first.
Note 1: 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.
Note 2: A similar question was also asked in CUET (UG) 2026 on 14-05-2026 (Slot 1).
NCERT Extract:
Decomposition – …
