Which of the following processes of decomposition produces a substance resistant to microbial action?

Options

A. catabolism
B. mineralisation
C. humification
D. leaching

Answer

To solve the question "Which of the following processes of decomposition produces a substance resistant to microbial action?", we can follow these steps:

### Step-by-step Solution:

1. **Understanding Decomposition**: Decomposition is the process by which organic substances are broken down into simpler organic or inorganic matter. This process is crucial for nutrient cycling in ecosystems.

2. **Identifying the Processes**: There are various processes of decomposition, including:
- **Putrefaction**: Decomposition of organic matter by bacteria and fungi, typically leading to foul odors.
- **Mineralization**: The process where organic matter is converted into inorganic substances.
- **Humification**: The process that leads to the formation of humus, a dark, organic material in soil.

3. **Focus on Humification**: Among these processes, humification is specifically important because it results in the formation of humus. Humus is characterized by its dark color and amorphous structure and is composed of partially decomposed organic matter.

4. **Properties of Humus**: Humus is rich in complex organic compounds such as cellulose, lignin, tannins, and resins. These compounds are highly resistant to microbial action, meaning that they decompose very slowly. This resistance is crucial for maintaining soil fertility and structure.

5. **Conclusion**: Since humification leads to the production of humus, which is resistant to microbial action, the correct answer to the question is **humification**.

### Final Answer:
The process of decomposition that produces a substance resistant to microbial action is **humification**.