Which one of the following does not favour decomposition?

The correct answer is Option (3) → Low temperature and anaerobiosis

Decomposition is the breakdown of dead organic matter (detritus) into simple inorganic substances by decomposers, mainly bacteria and fungi. Its rate depends on what the detritus is made of and on the climate.

Option (1) Oxygen — Favours decomposition. Decomposition is largely an oxygen-requiring process. The microbes that do most of it need oxygen for their respiration.

Option (2) Nitrogen and water-soluble sugars — Favours decomposition. Detritus rich in nitrogen and sugars is broken down quickly. Detritus rich in lignin and chitin decomposes slowly.

Option (3) Low temperature and anaerobiosis — Does not favour decomposition. Cold slows down the soil microbes, and anaerobiosis means there is no oxygen. Both inhibit decomposition, so organic matter builds up, as in cold or waterlogged soils.

Option (4) Warm and moist environment — Favours decomposition. Temperature and soil moisture are the main climatic factors. Warmth and moisture make soil microbes more active, so dead matter is broken down faster.

NCERT Extract:
Decomposition – …