Incomplete burning of fuels produces carbon monoxide.

Answer

**Step-by-Step Solution:**

1. **Understanding Combustion**:
- Combustion is a chemical reaction that occurs when a substance (usually a fuel) reacts with oxygen to produce heat and light.
- There are two types of combustion: complete combustion and incomplete combustion.

2. **Complete Combustion**:
- In complete combustion, a fuel burns in the presence of sufficient oxygen.
- The products of complete combustion are primarily carbon dioxide (CO2) and water (H2O).
- Example: When methane (CH4) burns completely, it produces CO2 and H2O.

3. **Incomplete Combustion**:
- Incomplete combustion occurs when there is insufficient oxygen for the fuel to react completely.
- This results in the production of carbon monoxide (CO) along with other products, such as soot or unburned hydrocarbons.
- Example: When methane burns with limited oxygen, it can produce CO instead of CO2.

4. **Carbon Monoxide**:
- Carbon monoxide is a colorless, odorless gas that is toxic to humans and animals.
- It is produced during the incomplete combustion of fuels, making it a dangerous byproduct.

5. **Conclusion**:
- The statement "incomplete burning of fuels produces carbon monoxide" is true.
- This is because incomplete combustion occurs due to insufficient oxygen, leading to the formation of CO instead of CO2.

**Final Answer**: The statement is true.

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