In PCR, Taq polymerase is used between

Options

A. Extraction and denaturation
B. Denaturation and annealing
C. Annealing and extension
D. Extension and amplification

Answer

### Step-by-Step Solution:

1. **Understanding PCR**: Polymerase Chain Reaction (PCR) is a technique used to amplify specific segments of DNA. It involves several key steps: denaturation, annealing, and extension.

2. **Identify the Role of Taq Polymerase**: Taq polymerase is a special enzyme used in PCR. It is derived from the thermophilic bacterium Thermus aquaticus, which allows it to withstand the high temperatures used in the PCR process.

3. **Recognizing the Steps of PCR**:
- **Denaturation**: The double-stranded DNA is heated to separate it into two single strands.
- **Annealing**: The temperature is lowered to allow primers to bind to the single-stranded DNA.
- **Extension**: The temperature is raised again, allowing Taq polymerase to synthesize new DNA strands by adding nucleotides to the primers.

4. **Determining Where Taq Polymerase is Used**: Taq polymerase is specifically active during the extension phase of PCR, where it synthesizes new DNA strands. Therefore, it is used after the annealing step and before the next cycle begins.

5. **Conclusion**: Based on the sequence of steps in PCR, Taq polymerase is used between the annealing and extension steps.

### Final Answer:
In PCR, Taq polymerase is used between **annealing and extension**.

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