An effective measure to prevent global warming is

Options

A. Drip - irrigation
B. afforestation
C. to provide growth chambers
D. None

Answer

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for an effective measure to prevent global warming from the given options.

2. **Identify the Problem**: Global warming is primarily caused by the emission of greenhouse gases into the atmosphere, such as CO2 and methane. These gases trap heat and prevent it from escaping, leading to an increase in Earth's temperature.

3. **Analyze the Options**:
- **Reforestation**: This involves planting trees in areas where forests have been cut down. It helps in absorbing CO2 from the atmosphere.
- **Afforestation**: This is the process of planting trees in areas that were not previously forested. It increases the number of trees, which absorb CO2 and release oxygen.
- **Provide Road Chambers**: This option does not directly relate to reducing greenhouse gases or preventing global warming.
- **None**: This option implies that none of the provided measures are effective, which is not accurate.

4. **Evaluate the Most Effective Measure**: Among the options, afforestation stands out as a proactive measure that directly increases the number of trees, thereby enhancing CO2 absorption and oxygen production. This can help mitigate the effects of global warming.

5. **Conclusion**: Based on the analysis, the most effective measure to prevent global warming is **afforestation**.

### Final Answer:
The correct option is **Afforestation**.

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