Plasmids are the most widely used cloning vectors in the technique of gene manipulation in bacteria.

Explanation

**Step-by-Step Solution:**

1. **Understanding Plasmids**: Plasmids are small, circular, double-stranded DNA molecules that are separate from chromosomal DNA. They are found in bacteria and can replicate independently.

2. **Definition of Cloning Vectors**: Cloning vectors are DNA molecules used to transport foreign genetic material into another cell. In the context of gene manipulation, plasmids serve as cloning vectors.

3. **Self-Replication**: Plasmids are self-replicating, meaning they can duplicate themselves within a host cell. This characteristic is crucial for cloning, as it allows the inserted gene to be copied along with the plasmid.

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