According to the three domain classification , Methanococcus and Rhizobium belong to

Options

A. same domain and different kingdom.
B. same domain and same kingdom .
C. different domain and different kingdom.
D. different domain and same kingdom

Answer

To solve the question regarding the classification of Methanococcus and Rhizobium according to the three-domain system, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Three-Domain Classification**:
- The three-domain classification system was proposed by Carl Woese and divides life into three main domains: Archaea, Bacteria, and Eukarya.

2. **Identify the Organisms**:
- Methanococcus is a genus of Archaea, which are known for their ability to produce methane and thrive in extreme environments.
- Rhizobium is a genus of bacteria that forms symbiotic relationships with leguminous plants, helping them fix nitrogen.

3. **Determine the Domains**:
- Since Methanococcus belongs to the domain Archaea, it is classified under Archaea.
- Rhizobium, being a bacterium, falls under the domain Bacteria.

4. **Compare the Domains**:
- Methanococcus (Archaea) and Rhizobium (Bacteria) belong to different domains.

5. **Determine the Kingdoms**:
- Methanococcus belongs to the kingdom Archaea.
- Rhizobium belongs to the kingdom Bacteria.

6. **Conclusion**:
- Since Methanococcus and Rhizobium belong to different domains (Archaea and Bacteria) and different kingdoms (Archaea and Bacteria), the correct answer is that they belong to different domains and different kingdoms.

### Final Answer:
- The correct option is: **Different domain and different kingdom**.

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