A gaint rat is formed in the laboratory. What is the reason ?

Options

A. Gene mutation
B. Gene sythesis
C. Gene manipulation
D. Gene replication

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks about the reason behind the formation of a giant rat in the laboratory.

2. **Identifying the Process**: The formation of a giant rat is primarily due to a technique known as **genetic engineering**. This process involves altering the genome of an organism.

3. **Genome Alteration**: In the case of the giant rat, the mouse genome is either completely or partially altered. This alteration is done to study various genes and their functions.

4. **Purpose of Genetic Engineering**: The genetically modified mice (in this case, a giant rat) serve as **animal models** for research. They are used to test various vaccines and study human diseases.

5. **Role of Growth Hormone**: Specifically, in the creation of the giant rat, a **growth hormone** is introduced into the fertilized egg of the mouse. This hormone leads to increased growth, resulting in the formation of a giant rat.

6. **Conclusion**: Therefore, the reason for the formation of the giant rat is **gene manipulation**, which allows for the introduction of growth hormones and other genetic modifications.

### Final Answer:
The reason for the formation of a giant rat in the laboratory is **gene manipulation** through genetic engineering techniques, specifically involving the introduction of growth hormones into the mouse genome.

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