Which of the following groups of plants are highly useful in
increasing soil fertility

Options

A. Algae
B. Fungi
C. Bacteria
D. Bacteriophage

Answer

To determine which group of plants is highly useful in increasing soil fertility, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are algae, fungi, bacteria, and bacteriophage.

2. **Evaluate Algae**:
- Algae can contribute to the organic carbon content of the soil when they decompose.
- However, they do not significantly enhance soil fertility directly.
- **Conclusion**: Algae are not the correct answer.

3. **Evaluate Fungi**:
- Some fungi form symbiotic relationships with the roots of higher plants, such as mycorrhizae.
- This association can enhance nutrient uptake for plants, which may indirectly contribute to soil fertility.
- However, not all fungi have this beneficial effect.
- **Conclusion**: Fungi are not the best choice for increasing soil fertility.

4. **Evaluate Bacteria**:
- Certain bacteria, both free-living and symbiotic, are known for their role in nitrogen fixation.
- Nitrogen-fixing bacteria convert atmospheric nitrogen into forms that plants can use, significantly enhancing soil fertility.
- **Conclusion**: Bacteria are highly useful in increasing soil fertility.

5. **Evaluate Bacteriophage**:
- Bacteriophages are viruses that infect bacteria.
- They do not contribute to soil fertility and primarily affect bacterial populations.
- **Conclusion**: Bacteriophages do not play a role in increasing soil fertility.

6. **Final Answer**: Based on the evaluations, the group of plants that is highly useful in increasing soil fertility is **C. Bacteria**.