Azotobacter and Beijerinckia are examples of :

Options

A. Symbiotic nitrogen fixers
B. Non-symbiotic nitrogen fixers
C. Ammonifying bacteria
D. Disease causing bacteria

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the classification of Azotobacter and Beijerinckia. We need to identify what type of bacteria these are in the context of nitrogen fixation.

2. **Identifying Nitrogen Fixation**: Nitrogen fixation is the process of converting atmospheric nitrogen (N₂) into a form that plants can use, such as ammonia or organic nitrogen compounds.

3. **Types of Nitrogen Fixers**:
- **Symbiotic Nitrogen Fixers**: These bacteria form a symbiotic relationship with plants, providing them with nitrogen in exchange for carbohydrates. An example is Rhizobium, which associates with legumes.
- **Non-Symbiotic Nitrogen Fixers**: These bacteria can fix nitrogen independently and do not form a symbiotic relationship with plants. Azotobacter and Beijerinckia fall into this category.

4. **Conclusion**: Since Azotobacter and Beijerinckia are known to fix nitrogen without forming a symbiotic relationship with plants, they are classified as non-symbiotic nitrogen fixers.

5. **Final Answer**: Azotobacter and Beijerinckia are examples of **non-symbiotic nitrogen fixers**.

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