Petroleum is a complex mixture of solid liquid and gaseous hydrocarbons, mixed with salt water and earthy particles. It is always found trapped between two impervious rocks. It is believed that petroleum is formed by the anaerobic decomposition of extremely small sea animals and plants which got buried in the sea bed millions of years ago.
Read the below questions and try to answer them.
Name the method by which petroleum is refined.

Explanation

To answer the question about the method by which petroleum is refined, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Composition of Petroleum**:
- Petroleum is a complex mixture that includes solid, liquid, and gaseous hydrocarbons, along with salt water and earthy particles.

2. **Know the Formation of Petroleum**:
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