Select an incorrect match

Options

A. Rhodospirillum - Photosynthetic nitrogen fixer
B. Bacillus - Symbiotic ` N_2 ` fixer
C. Alnus - Frankia
D. Azotobacter - Free living, aerobic `N_ 2 ` fixer

Answer

To solve the question "Select an incorrect match," we need to analyze each pair provided in the question and determine whether the descriptions of the organisms are accurate.

### Step-by-Step Solution:

1. **Analyze the First Pair: Rhodospirillum - Photosynthetic Nitrogen Fixer**
- Rhodospirillum is a type of gram-negative bacteria known for its ability to perform photosynthesis and fix nitrogen.
- **Conclusion**: This is a correct match.

2. **Analyze the Second Pair: Bacillus - Symbiotic Nitrogen Fixer**
- Bacillus is a genus of bacteria that is not known for forming symbiotic relationships for nitrogen fixation. Instead, it is typically involved in other processes, such as decomposition.
- **Conclusion**: This is an incorrect match.

3. **Analyze the Third Pair: Alnus - Francia**
- Alnus (commonly known as alder) is a plant that forms a symbiotic relationship with the bacteria Frankia, which is known for nitrogen fixation.
- **Conclusion**: This is a correct match.

4. **Analyze the Fourth Pair: Azotobacter - Free Living Aerobic Nitrogen Fixer**
- Azotobacter is indeed a free-living bacterium that can fix nitrogen in aerobic conditions.
- **Conclusion**: This is a correct match.

### Final Conclusion:
The incorrect match is the second pair: **Bacillus - Symbiotic Nitrogen Fixer**.