Assertion (A) : Thermus aquaticus, is used in PCR technique. Reason (R): It is a heat-stable DNA polymerase.

Options

A. Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
B. Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
C. Assertion (A) is true but reason (R) is false.
D. Assertion (A) is false but reason (R) is true.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion (A)**: The assertion states that Thermus aquaticus is used in the PCR technique. This is true because Thermus aquaticus is a thermophilic bacterium that is known for its ability to survive in high-temperature environments.

2. **Understanding the Reason (R)**: The reason given is that Thermus aquaticus produces a heat-stable DNA polymerase. This is also true. The DNA polymerase derived from Thermus aquaticus is known as Taq polymerase, which is essential for the PCR process.

3. **Explaining the Role of Taq Polymerase in PCR**: In the PCR technique, DNA needs to be amplified, which requires a DNA polymerase enzyme to synthesize new DNA strands. Taq polymerase is specifically used because it remains active at high temperatures, which is necessary for the denaturation step of PCR where the DNA strands are separated.

4. **Temperature Tolerance**: Taq polymerase can withstand temperatures around 92°C during the denaturation phase and operates optimally at around 72°C for the extension phase. This heat stability is crucial for the repeated cycles of heating and cooling in PCR.

5. **Conclusion**: Since both the assertion and the reason are true, and the reason correctly explains why Thermus aquaticus is used in PCR, we can conclude that both statements are correct.

**Final Answer**: Both Assertion (A) and Reason (R) are true, and the reason correctly explains the assertion.

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