The correct answer is (C) Microorganisms increase the production of humus, which leads to an increase in soil health.
Successive decomposition of organic matter leads to the formation of humus. Microorganism present in the soil speeds up the rate of decomposition of organic matter. Different products such as carbon dioxide, nutrients are released in the soil that contributes in soil health. This is called as Humification. This makes the soil color dark and increases the ability to retain nutrients in it. Humification also increases the level of phosphorous and nitrogen in the soil.
