Define cracking and give an example.

Explanation

### Step-by-Step Solution:

1. **Definition of Cracking**:
- Cracking is a chemical process in which heavy hydrocarbon molecules are broken down into lighter hydrocarbon molecules. This process typically involves the application of heat and may occur in the presence of high pressure and catalysts.

2. **Types of Cracking**:
- There are two main types of cracking:
- **Thermal Cracking**: This involves breaking down hydrocarbons using high temperatures and pressures without the use of a catalyst.
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