Decomposition — NEET Biology Questions

Practice 30 questions on Decomposition from Ecosystem (NCERT Class 12, Chapter 12). Free samples below — get all 30 in the app.

30 Questions Ecosystem Class 12

Sample Questions — Decomposition

Try 5 questions below from Decomposition. Get all 30 in the MedicNEET app.

MCQ
In what way does humus benefit plant growth despite decomposing slowly?
  • A. It stores carbon dioxide and essential minerals
  • B. It generates root pressure
  • C. It prevents mineralisation
  • D. It serves as a slow-release nutrient reservoir
✅ Correct Answer: D
Being colloidal, humus holds nutrients and gradually releases them into the soil.
MCQ
What makes humus stable and long-lasting in soil?
  • A. High water content
  • B. Reactive nitrogen compounds
  • C. Rich in glucose
  • D. Resistance to microbial action
✅ Correct Answer: D
Humus decomposes extremely slowly because it resists microbial degradation.
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MCQ
Match the decomposition product or condition (Column I) with its description (Column II): Column I A. Humus B. Mineralisation C. Warm, moist environment D. Oxygen availability Column II 1. Releases inorganic nutrients 2. Stable colloidal nutrient reservoir 3. Enhances microbial activity 4. Required for aerobic decomposition
  • A. A–2, B–1, C–3, D–4
  • B. A–1, B–2, C–3, D–4
  • C. A–2, B–3, C–4, D–1
  • D. A–3, B–4, C–1, D–2
✅ Correct Answer: A
Humus = colloidal, nutrient-rich; Mineralisation = releases inorganic nutrients; Warm, moist = accelerates microbial activity; Oxygen = necessary for aerobic breakdown.
MCQ
Which of the following organisms is an example of a detritivore?
  • A. Earthworm
  • B. Zooplankton
  • C. Fungi
  • D. Phytoplankton
✅ Correct Answer: A
Earthworm is a detritivore, aiding in the fragmentation of detritus.
MCQ
Assertion (A): Cold, anaerobic conditions promote rapid decomposition. Reason (R): Microbial activity is enhanced at low temperatures. Which option correctly describes A and R?
  • A. Both A and R are true, and R is the correct explanation of A
  • B. Both A and R are true, but R is not the correct explanation of A
  • C. A is true, R is false
  • D. Both A and R are false
✅ Correct Answer: D
Decomposition is slowed in cold, anaerobic conditions due to suppressed microbial activity.

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