"Three Gorges" is the one among the following choices given in the question that is a physical feature located only in China. The correct option among all the options that are given in the question is the third option or option "C". I hope the answer has come to your great help :-)
The living microbial biomass includes<span> the microorganisms responsible for decomposition (breakdown) of both plant residues and active </span>soil organic matter<span> or detritus. Humus is the stable fraction of the </span>soil organic matter<span> that is formed from decomposed plant and animal tissue. It is the final product of decomposition.</span>
