Concept:Decomposer microbes need favourable soil conditions to remain active and break down organic matter efficiently.
Explanation:Bacteria and fungi are the main decomposers in the soil.
Their activity is fastest when the soil
pH is near neutral, or at an optimum level for their growth.
Waterlogged soil lacks oxygen, so aerobic decomposers cannot work well.
Anaerobic conditions also slow decomposition and produce different end products.
Low soil temperature reduces microbial enzyme activity and reproduction.
Thus, only optimum soil
pH supports the best functioning of decomposing microorganisms.
Answer:D. optimum soil
pH