Which of the following tools are essential for recombenant DNA technology .
A. Vectors
B.Polymerase enzyme .
C. Restricition enzyme .
D . Ligase enzymes .

Options

A. A,B
B. B,C
C. C,D
D. all are correct

Answer

To determine which tools are essential for recombinant DNA technology, let's analyze each option provided:

1. **Vectors (Option A)**: Vectors are essential in recombinant DNA technology as they are used to carry the foreign DNA into the host cell. Common vectors include plasmids, which are circular DNA molecules that can replicate independently within a cell. Therefore, vectors are indeed essential.

2. **Polymerase Enzyme (Option B)**: Polymerase enzymes, specifically DNA polymerases, are crucial for DNA replication. When recombinant DNA is created, it needs to be replicated within the host organism. Thus, polymerase enzymes are also essential for the process.

3. **Restriction Enzyme (Option C)**: Restriction enzymes are vital for cutting DNA at specific sequences. They allow scientists to isolate the desired DNA fragment from the source organism and prepare it for insertion into the vector. Therefore, restriction enzymes are essential.

4. **Ligase Enzymes (Option D)**: Ligase enzymes are responsible for sealing the nicks in the sugar-phosphate backbone of the DNA after the desired DNA fragment has been inserted into the vector. This joining process is crucial for the formation of recombinant DNA. Hence, ligase enzymes are also essential.

After analyzing all the options, we conclude that all the tools listed (A, B, C, and D) are essential for recombinant DNA technology.

### Final Answer:
**All of the above tools (A, B, C, D) are essential for recombinant DNA technology.**

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