A : Methanogens can show symbiotic association with eukaryotic organisms.
R : They are used for the production of biogas.

Options

A. If both assertion & reason are true and the reason is the correct explanation of the assertion
B. If both assertion & reason are true but the reason is not the correct explanation of the assertion
C. If assertion is true statement but reason is false
D. If both assertion and reason are false statements

Answer

To solve the assertion and reason question regarding methanogens, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion (A): Methanogens can show symbiotic association with eukaryotic organisms.**

- **Definition of Methanogens**: Methanogens are a group of microorganisms, specifically archaea, that produce methane as a metabolic byproduct in anoxic conditions.
- **Symbiotic Association**: Symbiosis refers to a close and often long-term interaction between two different biological species. In this case, methanogens can live in symbiotic relationships with eukaryotic organisms, such as in the guts of ruminants (like cows) where they help digest food by breaking down complex organic materials.

**Conclusion for Assertion**: The assertion is true because methanogens do indeed form symbiotic relationships with eukaryotic organisms.

### Step 2: Analyze the Reason
**Reason (R): They are used for the production of biogas.**

- **Biogas Composition**: Biogas is primarily composed of methane, along with carbon dioxide and small amounts of other gases. Methanogens are crucial in the production of biogas as they break down organic matter anaerobically, producing methane.
- **Use of Methanogens**: Methanogens are utilized in biogas production processes, especially in anaerobic digesters, where they help convert organic waste into biogas.

**Conclusion for Reason**: The reason is also true because methanogens are indeed used for the production of biogas.

### Step 3: Determine the Relationship between Assertion and Reason
- While both the assertion and reason are true, the reason does not directly explain why methanogens can show symbiotic associations with eukaryotic organisms. The assertion speaks about the relationship between methanogens and eukaryotes, while the reason discusses their role in biogas production.

### Final Conclusion
Both the assertion and reason are true statements, but the reason is not the correct explanation for the assertion. Therefore, the answer is:

**Option B: Assertion and reason are true, but reason is not the correct explanation of the assertion.**

---