Fossil fuels are an inexhaustible natural resource of fuel.

Answer

### Step-by-Step Solution:

1. **Understanding the Terms**:
- First, we need to clarify the terms "exhaustible" and "inexhaustible."
- **Exhaustible** means that a resource is available in limited quantity and can be depleted over time.
- **Inexhaustible** means that a resource is available in unlimited quantity and cannot be depleted.

2. **Analyzing Fossil Fuels**:
- Fossil fuels, such as coal, oil, and natural gas, are formed from the remains of ancient plants and animals over millions of years.
- These fuels are extracted and used for energy production, but they take millions of years to form.

3. **Determining the Nature of Fossil Fuels**:
- Since fossil fuels are formed over such a long time and are being consumed at a much faster rate than they are formed, they are considered to be in limited supply.
- Therefore, fossil fuels are classified as exhaustible resources.

4. **Conclusion**:
- The statement "Fossil fuels are an inexhaustible natural resource of fuel" is false.
- The correct statement is that fossil fuels are exhaustible natural resources.

### Final Answer:
Fossil fuels are an exhaustible natural resource of fuel, not inexhaustible.

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