Largest among non sulpher bacteria are

Options

A. Vibrio
B. Bacillus subtilis
C. Spirillum
D. E.coli

Answer

To determine the largest non-sulfur bacteria, we will evaluate the given options step by step.

### Step 1: Analyze the First Option - Vibrio
- **Description**: Vibrio are characterized as facultative anaerobes.
- **Size**: The length of Vibrio bacteria is approximately 1.5 to 3.0 micrometers.
- **Conclusion**: Since the size is relatively small, Vibrio is not the largest non-sulfur bacteria.

### Step 2: Analyze the Second Option - Bacillus subtilis
- **Description**: Bacillus subtilis is a gram-positive bacterium commonly found in the gastrointestinal tract of ruminants and humans.
- **Size**: The size of Bacillus subtilis is also not the largest among non-sulfur bacteria.
- **Conclusion**: Therefore, Bacillus subtilis is not the correct answer.

### Step 3: Analyze the Third Option - Spirulina
- **Description**: Spirulina is a type of cyanobacteria (often referred to as blue-green algae) and is known for its large size.
- **Size**: Spirulina can grow to lengths of about 5 to 8 micrometers.
- **Conclusion**: This makes Spirulina the largest among the non-sulfur bacteria.

### Step 4: Analyze the Fourth Option - E. coli
- **Description**: Escherichia coli (E. coli) is a common bacterium found in the intestines of humans and animals.
- **Size**: E. coli typically measures around 1 to 2 micrometers in length.
- **Conclusion**: E. coli is also not the largest non-sulfur bacteria.

### Final Conclusion
After analyzing all the options, the correct answer is **Spirulina**, as it is the largest among non-sulfur bacteria.

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