Give two examples of each : Fossil fuel

Explanation

### Step-by-Step Solution:

1. **Understanding Fossil Fuels**:
- Fossil fuels are natural substances that are formed from the remains of dead organisms that have been buried under layers of earth for millions of years. These remains undergo a process of decomposition due to heat and pressure, resulting in the formation of fossil fuels.

2. **Definition**:
- A fossil fuel is defined as a fuel that is formed from the decomposition of buried dead organisms under pressure and heat in the Earth's crust.

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