[A]: Plasmids are small accessory rings of DNA found in some bacteria that carry genes.
[R]: Plasmids that are used as a vector have been removed from bacteria and have had a foreign gene inserted into them

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

**Step-by-Step Solution:**

1. **Understanding the Assertion**: The assertion states that plasmids are small accessory rings of DNA found in some bacteria that carry genes. This is true because plasmids are indeed small, circular pieces of DNA that exist independently of chromosomal DNA in bacteria. They often carry genes that can provide advantages, such as antibiotic resistance.

2. **Understanding the Reason**: The reason provided states that plasmids used as vectors have been removed from bacteria and have had a foreign gene inserted into them. This is also true. In genetic engineering, plasmids are often extracted from bacteria, modified to include foreign genes, and then reintroduced into bacteria or other cells to facilitate gene cloning or expression.

3. **Evaluating the Relationship**: The next step is to determine if the reason is a correct explanation of the assertion. Since plasmids are indeed used as vectors in genetic engineering, and the process involves removing them from bacteria and inserting foreign genes, the reason does correctly explain the assertion.

4. **Conclusion**: Both the assertion and the reason are true, and the reason is the correct explanation of the assertion. Therefore, the correct answer is option 1: both assertion and reason are true, and reason is the correct explanation of assertion.

**Final Answer**: Option 1 - Both assertion and reason are true, and reason is the correct explanation of assertion.

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