Disease like malaria and filariasis are transmitted through insect vectors. Vectors can be controlled by introducing fish

Options

A. Labeo
B. Gambusia
C. Hisla
D. Catla

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question states that diseases like malaria and filariasis are transmitted through insect vectors. It asks which fish can be introduced to control these vectors.

2. **Identifying the Vectors**: Malaria is primarily transmitted by Anopheles mosquitoes, while filariasis is transmitted by various species of mosquitoes, including Culex and Aedes. Therefore, controlling mosquito populations can help reduce the incidence of these diseases.

3. **Biological Control Method**: One effective method of controlling mosquito populations is through biological control, which involves introducing natural predators of mosquito larvae into water bodies where mosquitoes breed.

4. **Evaluating the Options**: The options provided are:
- Labio
- Gambusia
- Hisla
- Ketla

5. **Identifying the Correct Fish**: Among the options, Gambusia (specifically Gambusia affinis) is known as the mosquito fish. It is effective in controlling mosquito populations because it feeds on mosquito larvae.

6. **Conclusion**: Therefore, the correct answer to the question is Gambusia, as it is the fish that can be introduced to control the vectors responsible for transmitting malaria and filariasis.

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

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