Concept:Decomposer microorganisms require a favourable soil environment, especially a balanced
pH, for maximum activity.
Explanation:Microorganisms that decompose organic matter are called decomposers.
They function best when the soil
pH is near neutral, i.e. around
pH=7.
This optimum
pH supports their growth, enzyme activity, and metabolic processes.
Low soil temperature, anaerobic conditions, and waterlogged soil reduce microbial activity and slow decomposition.
Therefore, among the given options, optimum soil
pH is the most suitable condition.
Answer:A. optimum soil
pH