About 95% of all existing transgenic animals are ________ .

Options

A. Rabbits
B. Pigs
C. Cows
D. Mice

Answer

**Step-by-Step Solution:**

1. **Understanding Transgenic Animals**: Transgenic animals are those whose genetic material has been altered through genetic engineering. This manipulation allows them to express new traits or characteristics that are not naturally found in their species.

2. **Examples of Transgenic Animals**: Various animals can be genetically modified, including rabbits, cows, pigs, sheep, and mice. These animals are used in scientific research for various purposes, such as studying diseases, testing drugs, and understanding genetic functions.

3. **Identifying the Most Common Transgenic Animal**: Among all these transgenic animals, mice are the most commonly used. It is noted that about 95% of all existing transgenic animals are mice.

4. **Reasons for the Prevalence of Mice**: Mice are favored in research for several reasons:
- They have a short reproductive cycle, allowing for rapid breeding and generation of offspring.
- They are genetically similar to humans, making them suitable for studying human diseases.
- They are relatively inexpensive and easy to maintain in laboratory settings.

5. **Conclusion**: Therefore, the answer to the question is that about 95% of all existing transgenic animals are mice.

**Final Answer**: About 95% of all existing transgenic animals are **mice**.

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