Decomposition is largely an oxygen-requiring process. The rate of decomposition is controlled by chemical composition of detritus and climatic factors. In a particular climatic condition, decomposition rate is slower if detritus is rich in lignin and chitin, and quicker, if detritus is rich in nitrogen and water-soluble substances like sugars. Temperature and soil moisture are the most important climatic factors that regulate decomposition through their effects on the activities of soil microbes. Warm and moist environment favour decomposition whereas low temperature and anaerobiosis inhibit decomposition resulting in build up of organic materials.
NTA tests whether students understand that decomposition rate depends on both detritus composition (nitrogen, water-soluble substances speed it up; lignin and chitin slow it down) and climatic conditions (warm, moist environments favor it; low temperature and anaerobic conditions inhibit it). Students commonly mistake thinking that ALL organic material decomposes at the same rate, ignoring how chemical composition matters. The key trap is confusing which substances speed up vs. slow decomposition—remember nitrogen-rich material decomposes faster while woody/chitinous material decomposes slower. Always connect environmental conditions to microbial activity: microbes work faster in warm, wet, oxygen-rich conditions.
This paragraph was tested 2 times in NEET.
(NEET 2024) Given below are two statements: Statement I: The rate of decomposition is not related to the chemical composition of detritus and climatic factors. Statement II: In a particular climatic condition, decomposition rate is faster if detritus is rich in lignin and chitin. In light of the above statements, choose the correct answer:
(NEET 2022 – Phase 1) Given below are two statements: Statement I: Decomposition is a process in which the detritus is degraded into simpler substances by microbes. Statement II: Decomposition is faster if the detritus is rich in lignin and chitin. Choose the correct option:
MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.