….... leads to accumulation of a dark coloured amorphous substance called ....... that is highly resistant to microbial action and undergones decomposition at an extremely slow rate.

Options

A. Humification , humus
B. Mineralisation , minerals
C. Fragmentation , detritus
D. Leaching, unavailable salts

Answer

To solve the question, we need to identify the process that leads to the accumulation of a dark-colored amorphous substance that is resistant to microbial action and decomposes at a very slow rate.

### Step-by-Step Solution:

1. **Understanding the Process**: The question asks for a process that results in the formation of a dark-colored substance. This process is related to the breakdown of organic matter.

2. **Identifying the Substance**: The substance described is dark-colored and amorphous, which suggests it is a type of organic matter that has undergone significant transformation.

3. **Analyzing the Options**:
- **Hemification**: This is the process where organic matter is transformed into humus, a dark-colored, amorphous substance that is resistant to microbial action and decomposes very slowly.
- **Mineralization**: This refers to the conversion of organic matter into inorganic substances, not specifically to the formation of a dark substance.
- **Fragmentation**: This is the breaking down of organic matter into smaller pieces but does not lead to the formation of the specific dark substance mentioned.
- **Leaching**: This involves the removal of soluble substances from the soil and does not relate to the formation of a dark amorphous substance.

4. **Conclusion**: The correct process that leads to the accumulation of the dark-colored amorphous substance is **Hemification**, and the substance formed is **Humus**.

### Final Answer:
The process is **Hemification**, and the dark-colored amorphous substance is called **Humus**.

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