Floods can be prevented by

Options

A. Making the soil less sloppy
B. Removing forests
C. Removing soil cover
D. Planting trees on slopes and building dams

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks how floods can be prevented. Flood prevention involves various methods that can help manage water flow and reduce the risk of flooding.

2. **Identifying Options**: The options provided are:
- Making the soil less slopey
- Removing forest
- Removing soil cover
- Planting trees on slopes
- Building dams

3. **Analyzing Each Option**:
- **Making the soil less slopey**: This does not directly prevent floods. While flatter land may reduce runoff, it does not address the overall flood risk.
- **Removing forest**: Deforestation can increase the risk of flooding as it reduces the interception of rainfall and increases runoff. This option is incorrect.
- **Removing soil cover**: Similar to deforestation, removing soil cover can lead to increased erosion and runoff, thus increasing flood risk. This option is also incorrect.
- **Planting trees on slopes**: This is a method of afforestation. Trees help to intercept rainfall, reduce runoff, and bind the soil, which can prevent soil erosion and reduce flood risk. This option is correct.
- **Building dams**: Dams can control water flow and store excess water, thus preventing floods downstream. This option is also correct.

4. **Conclusion**: The most effective options for preventing floods are "planting trees on slopes" and "building dams." Both methods contribute to managing water flow and reducing the likelihood of flooding.

### Final Answer:
Floods can be prevented by **planting trees on slopes** and **building dams**.

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