Q.Detritus are the raw materials for decomposition. There are several steps involved in this decomposition process. Name and explain the processes in which earth worm and bacteria carry on detritus.

Showing the 12 most recent of 18 on this concept.

1. CBSE 2026Set V11 markMCQ
   Q.Dead plant remains such as leaves, bark and flowers constitute

   (a) Debris

   (b) Humus

   (c) Detritus

   (d) Fossil

   ›Reveal solutionSolution

   Dead plant material (leaves, bark, flowers) plus dead animal remains form the detritus.

   In an ecosystem, dead plant remains such as leaves, bark and flowers, along with dead animal remains and faecal matter, constitute the detritus. Detritus is the raw material for the process of decomposition, in which detritivores and decomposers break it down. Humus is the dark, amorphous, partially decomposed and highly resistant organic matter that accumulates i …

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2. CBSE 2026Set A1 markMCQ
   Q.What is the raw material for decomposition called?

   (a) Humus

   (b) Inorganic substance

   (c) Detritus

   (d) Organic substance

   ›Reveal solutionSolution

   Decomposition acts on detritus — dead organic remains such as fallen leaves, dead bodies and faecal matter.

   Decomposition is the process by which decomposers break down complex organic matter into inorganic substances. The raw material for this process is detritus, which consists of dead plant remains (leaves, bark, flowers) and dead animal bodies and their faecal matter. Thro …

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3. CBSE 2026Set A1 markMCQ
   Q.What are those called which obtain energy and nutrition from breaking dead organic matter or detritus?

   (a) Saprotrophs

   (b) Heterotrophs

   (c) Detritivores

   (d) Parasite

   ›Reveal solutionSolution

   Detritivores feed on and break down detritus (dead organic matter) to obtain energy and nutrients.

   Detritivores, such as earthworms and many soil arthropods, feed on detritus — dead organic matter — and fragment it, obtaining their energy and nutrition from it. This fragmentation of detritus is an important early …

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4. CBSE 2025Set X11 markMCQ
   Q.In which of the processes given, the humus is degraded by some microbes and release of inorganic nutrients occur?

   (a) Leaching

   (b) Mineralisation

   (c) Catabolism

   (d) Humification

   ›Reveal solutionSolution

   The microbial breakdown of humus that releases inorganic nutrients is mineralisation.

   During decomposition, humus is further degraded by some microbes and this releases inorganic nutrients (like ammonium, nitrate, phosphate) back into the soil. This process is called mineralisation.

   • (a) Leaching is the movement of water-soluble inorganic nutrients down into the soil horizons where they get precipitated. …

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5. CBSE 2025Set A1 mark
   Q.Match the correct pair and write the match for 'Detritivorous'. Column I:

   (i) Apomixis

   (ii) Darwin

   (iii) Toddy

   (iv) Agarose

   (v) Detritivorous. Column II:

   (a) Galapagos Islands

   (b) Southern India

   (c) Sea weeds

   (d) Earthworm

   (e) Grass family.

   ›Reveal solutionSolution

   Detritivorous matches with (d) Earthworm, a well-known soil detritivore/decomposer.

   Detritivores are organisms that feed on detritus — the partially decomposed remains of dead plants and animals, and faecal matter. Earthworms are one of the most familiar detritivores, ingesting soil rich in organic detritus, digesting the organic fraction, and excreting nutrient-rich castings; in doing so, they also help b …

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6. CBSE 2025Set ANNUAL1 markMCQ
   Q.Decomposition would be fast if the detritus contains _____.

   (a) Cellulose

   (b) Lignin and chitin

   (c) Nitrogen and water soluble sugars

   (d) Cellulose and pectin

   ›Reveal solutionSolution

   The rate of decomposition of detritus is controlled by its chemical composition: detritus rich in nitrogen and simple, water-soluble substances like sugars decomposes rapidly, whereas detritus rich in lignin and chitin decomposes very slowly.

   Decomposition is the process by which decomposers (bacteria and fungi) break down complex organic matter in detritus into simpler inorganic substances (humus and minerals). The rate at which this happens is not the same for all detritus — it depends heavily on the quality of the detritus:

   • Nitrogen content and water-soluble substances (e.g. sugars): these are easy for microbes to metabolise quickly, so decomposition is rapid when they are abundant.
   • Lignin and chitin: these are structurally tough, recalcitrant biopolymers (lignin in woody/cellulosic material, chitin in fungal cell walls/insect exoskeletons) that resist microbial enzymatic breakdown, so detritus rich in them decomposes very slowly. …

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7. CBSE 2024Set GG1 markMCQ
   Q.Which one of the following is a detritivore?

   (a) Earthworm

   (b) Bird

   (c) Frog

   (d) Elephant

   ›Reveal solutionSolution

   A detritivore eats dead/decaying organic matter; the earthworm does exactly this, so the answer is (a).

   Concept. In an ecosystem, detritivores are organisms that feed on detritus — fragments of dead plants and animals and their waste. They fragment the detritus during feeding, aiding decomposition and nutrient recycling.

   …

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8. CBSE 2024Set E1 markMCQ
   Q.Going down of inorganic water soluble nutrients into the soil nutrients is called as

   (a) Fragmentation

   (b) Leaching

   (c) Catabolism

   (d) Humification

   ›Reveal solutionSolution

   Leaching = the process in decomposition where water-soluble inorganic nutrients percolate down into the soil.

   Decomposition of detritus involves several steps: fragmentation (breaking litter into pieces), leaching, catabolism, humification and mineralisation. During leaching, water-soluble inorganic nutrients dissolve in percolating water and move down (get precipitated) into the deeper soil layers, becoming unavailable to plants at the …

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9. CBSE 2024Set E1 markMCQ
   Q.Which of the following are decomposers?

   (a) Fungi and algae

   (b) Fungi and virus

   (c) Fungi and bacteria

   (d) Fungi, bacteria and virus

   ›Reveal solutionSolution

   Fungi and bacteria are the principal decomposers of an ecosystem.

   Decomposers (saprotrophs) break down the complex organic remains of dead plants and animals (detritus) into simple inorganic substances, recycling nutrients back to the soil:

   • FUNGI and BACTERIA secrete digestive enzymes onto the detritus and absorb the products — they are the main decomposers. …

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10. CBSE 2024Set BOTANY1 mark
    Q.Correct the statement, if necessary, by changing the underlined word(s) only: The process of accumulation of a dark-coloured amorphous substance in soil is called mineralization.

    ›Reveal solutionSolution

    The process described is humification, not mineralization.

    Decomposition of detritus proceeds through fragmentation, leaching, catabolism, humification, and mineralization. Humification leads to the accumulation of a dark-coloured, amorphous substance called humus, which is highly resistant to microbial action and decomposes very slowly, acting as a nutrient reservoir. Mineralization, on the other hand, is a distinct, later step in which microbes further degrade humus and release inorganic nutrients (like CO2, water, and m …

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11. CBSE 2024Set ANNUAL1 markMCQ
    Q.Bacteria and fungi are

    (a) producers

    (b) primary consumers

    (c) scavengers

    (d) decomposers

    ›Reveal solutionSolution

    Bacteria and fungi are the principal decomposers of an ecosystem, breaking down dead organic matter and recycling nutrients.

    Bacteria and fungi are saprotrophic organisms that obtain their nutrition by secreting digestive enzymes onto dead organic matter (detritus) and absorbing the resulting simpler breakdown products. Through this decomposition activity, they release inorganic nutrients back into the soil/environment for reuse by producers, making them the decomposers of an ecosystem. They are not producers (which are autotrophic …

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12. CBSE 2024Set ANNUAL1 markMCQ
    Q.The process by which inorganic nutrients go down into the soil horizon and gets precipitated as unavailable salts is called .............

    (a) Fragmentation

    (b) Leaching

    (c) Catabolism

    (d) Fermentation

    ›Reveal solutionSolution

    Leaching is the downward movement of nutrients through the soil where they get precipitated as unavailable salts.

    During nutrient cycling (biogeochemical cycles) in an ecosystem, inorganic nutrients in the soil can move downward through the soil horizons with percolating water and get precipitated as insoluble/unavailable salts at lower depths — this process is called leaching, and it represents a loss of nutrients from the topsoil reservoir. This is different from fragmentation (breakdown …

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