Which one of the following processes during decomposition is correctly described?
A. Fragmentation-Carried out by organisms such as earthworm
B. Humification-Leads to the accumulation of a dark coloured substance humus, which undergoes microbial action at a very fast rate
C. Catabolism-Last step in the decomposition under fully anaerobic condition
D. Leaching-Water soluble inorganic nutrients rise to the top layers of soil