Question

Go through the following processes of decomposition.
A. Humification: Process of formation of dark–coloured amorphous, slightly acidic substances, which are highly resistant to microbial action.
B. Fragmentation: Carried out by earthworm and termites.
C. Catabolism: Carried out by microorganisms under fully anaerobic conditions, by their extracellular enzymes. 
D. Leaching: Water–soluble organic nutrients go down into the soil layers and get precipitated.
The correctly described processes are:

• A. (A) and (C).
• B. (A), (B), and (C).
• C. (A) and (B).
• D. (A), (B), (C), and (D).

Answer 1

Answer: (C)

Fragmentation of Detritus: Small invertebrate animals called detritivores or detritophages feed on detritus, for example, earthworms, termites they bring about its fragmentation.
Leaching: Part of water-soluble substances present in the fragmented and decomposition detritus (for example, sugars, inorganic nutrients) go down into the soil horizon by percolating water and get precipitated as unavailable salts.

Catabolism: It is carried out by saprotrophic bacteria and fungi. They secrete digestive enzymes over the fragmented detritus. The enzymes degrade complex organic compounds into simple inorganic substances.
Humification: It is the process of decomposition of detritus to form humus. Humus is a dark-coloured, amorphous, more or less decomposed organic matter rich in cellulose, lignin, tannins, resin, etc. and is highly resistant against microbial action. It undergoes decomposition at an extremely slow rate. Humus is slightly acidic, colloidal, and functions as a reservoir of nutrients.