$ Sulphur depended archaebacteria are called thermoacidophiles.
! Archeopteryx is considered to be a connecting link between Birds and Reptiles.

Options

A. If both As and R are correct and R is correct explanation of As
B. If both As and R are correct but R is not correct explanation of As
C. If As is correct, R is wrong
D. If both As and R are wrong.

Answer

To address the question regarding the assertion and reason provided, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that sulfur-dependent archaebacteria are called thermoacidophiles.
- Thermoacidophiles are a type of archaebacteria that thrive in extreme environments, specifically high temperatures and acidic conditions.

2. **Characteristics of Thermoacidophiles**:
- These bacteria can survive in harsh conditions and are known for their ability to convert sulfur into sulfuric acid.
- The energy released during this conversion is utilized for their metabolic processes, including the production of food.

3. **Conclusion on the Assertion**:
- Since thermoacidophiles are indeed archaebacteria that depend on sulfur and can survive in extreme conditions, the assertion is correct.

4. **Understanding the Reason**:
- The reason states that Archaeopteryx is considered a connecting link between birds and reptiles.
- Archaeopteryx exhibits features of both birds (like feathers and wings) and reptiles (like teeth and a long tail), making it a significant fossil in understanding evolutionary biology.

5. **Conclusion on the Reason**:
- The reason is also correct as Archaeopteryx does represent a transitional form between birds and reptiles.

6. **Relationship Between Assertion and Reason**:
- While both the assertion and the reason are correct, the reason does not explain the assertion. The assertion is about the characteristics of thermoacidophiles, while the reason discusses Archaeopteryx, which is unrelated to the assertion.

7. **Final Answer**:
- Therefore, the correct answer is that both the assertion and reason are correct, but the reason is not the correct explanation of the assertion.