Plasmids are used in genetic engineering because they are

Options

A. easily available
B. able to replicate
C. able to integrate
D. inert

Answer

### Step-by-Step Solution:

1. **Understanding Plasmids**: Plasmids are small, circular pieces of DNA that are separate from chromosomal DNA and are commonly found in bacteria. They can replicate independently of the bacterial chromosome.

2. **Role in Genetic Engineering**: In genetic engineering, plasmids are used as vectors to transfer genetic material into host cells. This is crucial for cloning and expressing genes of interest.

3. **Replication Ability**: One of the key features of plasmids is their ability to replicate independently within a host cell. This means that once a plasmid containing a gene of interest is introduced into a bacterial cell, that cell can produce many copies of the plasmid, thereby amplifying the gene.

4. **Integration and Inertness**: While plasmids can integrate into the host genome, this is not their primary function in genetic engineering. They are not inert; they actively replicate and can carry genes into the host cells.

5. **Conclusion**: Therefore, the primary reason plasmids are used in genetic engineering is that they are able to replicate, allowing for the amplification of the desired genetic material.

### Final Answer:
Plasmids are used in genetic engineering because they are able to replicate.

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