What is the source of the Ti (Tumor inducing) plasmid which is modified and used as a cloning vecotr to deliver the desirable genes into plant cells?

Options

A. Agrobacterium tumifaciens
B. Thermophilus aquaticus
C. Pyrococcus furiosus
D. Aedes aegypti

Answer

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the source of the Ti (Tumor inducing) plasmid that is modified for use as a cloning vector in plant cells.

2. **Identifying the Function of Ti Plasmid**: The Ti plasmid is known for its role in inducing tumors in plants. It carries genes that can be transferred to plant cells, leading to the formation of tumors.

3. **Source of Ti Plasmid**: The Ti plasmid is derived from a specific bacterium that is pathogenic to plants.

4. **Naming the Bacterium**: The bacterium that contains the Ti plasmid is called *Agrobacterium tumefaciens*. This bacterium is found in soil and is known for its ability to transfer DNA to plant cells.

5. **Conclusion**: Therefore, the source of the Ti plasmid is *Agrobacterium tumefaciens*.

### Final Answer:
The source of the Ti (Tumor inducing) plasmid is *Agrobacterium tumefaciens*.

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