One of the advantages of developing transgenic mice is that it is very useful:

Options

A. To study vaccine safety
B. In producing new varieties of mice
C. In developing a show piece example
D. In gene targeting

Answer

### Step-by-Step Solution:

1. **Understanding Transgenic Mice**:
- Transgenic mice are genetically modified organisms where a specific gene has been inserted into their genome. This modification allows researchers to study the effects of that gene on the organism's biology.

2. **Purpose of Developing Transgenic Mice**:
- The primary purpose of creating transgenic mice is to use them as models for human diseases. This helps in understanding the disease mechanisms and testing potential treatments.

3. **Research Applications**:
- Transgenic mice are extensively used in biomedical research. They help in studying various aspects of diseases, including their progression, symptoms, and potential therapeutic interventions.

4. **Drug and Vaccine Testing**:
- Before any drug or vaccine is approved for human use, it must undergo rigorous testing on animal models. Mice are often the preferred choice due to their genetic, biological, and behavioral similarities to humans.

5. **Identifying the Correct Option**:
- Among the provided options, the one that states transgenic mice are useful for studying vaccine safety aligns with their primary application in research. This makes it the correct answer.

6. **Conclusion**:
- Therefore, the advantage of developing transgenic mice is that they are very useful in studying vaccine safety.

### Final Answer:
Transgenic mice are very useful for studying vaccine safety.

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