Decomposition & Nutrient Cycling — NEET Biology
📚 Practice ConceptDefine decomposition and describe the processes and products of decomposition.
Which of the following statements correctly describe the consequences of varying decomposition rates and the characteristics of its products? S1: A decrease in the rate of decomposition due to low temperature leads to a build-up of organic materials. S2: Detritus rich in lignin and chitin will decompose faster than detritus rich in nitrogen. S3: Anaerobic conditions enhance the process of humification, leading to the rapid breakdown of complex organic matter. S4: Humus, being resistant to microbial action, accumulates more readily under conditions that inhibit overall decomposition. S5: Mineralisation, the release of inorganic nutrients from humus, would be accelerated in cold, anaerobic environments.
View solution & NCERT explanation
Correct answer: A — S1 and S4 only
The core concept here is the impact of environmental factors on decomposition rates and the characteristics of humus. S1: NCERT states that low temperature and anaerobiosis inhibit decomposition, resulting in the build-up of organic materials. This statement is correct. S2: NCERT indicates that decomposition rate is slower if detritus is rich in lignin and chitin, and quicker if rich in nitrogen. Therefore, this statement is incorrect. S3: Anaerobic conditions inhibit decomposition. Humification leads to accumulation of humus, not rapid breakdown of complex organic matter which is characteristic of catabolism or mineralisation. This statement is incorrect. S4: Humus is highly resistant to microbial action. Conditions that inhibit overall decomposition (like low temperature, anaerobiosis) would slow down the degradation of humus, thus promoting its accumulation. This statement is correct. S5: Cold, anaerobic environments inhibit decomposition, which includes mineralisation. Therefore, mineralisation would be inhibited, not accelerated. This statement is incorrect. Thus, S1 and S4 are the correct statements.
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.