Carbonisation is:

Options

A. slow conversion of dead vegetation into coal
B. deposition of soil
C. falling of trees
D. none of these

Explanation

**Step-by-Step Solution:**

1. **Understanding Carbonization**: Carbonization is a process that involves the transformation of organic materials, particularly plant matter, into carbon-rich substances, primarily coal.

2. **Origin of Carbonization**: The process begins with the accumulation of dead plant material, which over time becomes buried under layers of soil and sediment.

3. **Conditions for Carbonization**: As the plant material is buried deeper, it is subjected to increased pressure and temperature. This environment leads to a slow chemical transformation.

4. **Pyrolysis Process**: During carbonization, the organic material undergoes pyrolysis, which is the thermal decomposition of materials at elevated temperatures in the absence of oxygen. This process breaks down the complex organic molecules into simpler carbon compounds.

5. **Formation of Coal**: Over millions of years, this slow conversion results in the formation of coal, which is primarily composed of carbon.

6. **Conclusion**: Therefore, carbonization can be defined as the slow conversion of dead vegetation into coal through the processes of heat and pressure over geological time.

**Final Answer**: Carbonization is the slow conversion of dead vegetation into coal.

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