A sheep named Dolly became famous because of

Options

A. embryo rescue
B. in bitro fertilization
C. cloning
D. transgenic animal

Answer

### Step-by-Step Solution:

1. **Identify the Context**: The question asks why a sheep named Dolly became famous. This requires understanding the significance of Dolly in the field of biotechnology.

2. **Recall Key Information**: Dolly was the first mammal to be cloned from an adult somatic cell. This groundbreaking achievement took place at the Roslin Institute in Scotland in July 1996.

3. **Understand Cloning**: Cloning refers to creating a genetically identical copy of an organism. In Dolly's case, she was cloned from a somatic cell, which is any cell of the body except sperm and egg cells.

4. **Recognize the Impact**: The successful cloning of Dolly demonstrated that it was possible to create a whole organism from a single somatic cell, which had significant implications for genetics, medicine, and biotechnology.

5. **Eliminate Other Options**:
- **Embryo Rescue**: This technique involves saving embryos that might not survive without intervention, which is not related to Dolly.
- **In Vitro Fertilization (IVF)**: This is a process of fertilizing an egg outside the body, which is also not applicable to Dolly's case.
- **Transgenic Animals**: These are animals that have had a foreign gene inserted into their genome, which does not describe Dolly.

6. **Conclude with the Correct Answer**: Therefore, Dolly became famous because she was the first mammal to be cloned from an adult somatic cell, making "cloning" the correct answer.

### Final Answer:
A sheep named Dolly became famous because of **cloning**.