Which of the following is the pair of biofertilizers

Options

A. Azolla and BGA
B. Nostoc and legume
C. Rhizobium and grasses
D. Salmonella & E. Coli

Answer

To solve the question "Which of the following is the pair of biofertilizers?", we will analyze each option provided and identify which pair consists of biofertilizers.

### Step-by-Step Solution:

1. **Understand the Definition of Biofertilizers**:
Biofertilizers are substances that contain living microorganisms, which promote plant growth by increasing the availability of nutrients to the plants. Common examples include certain bacteria and cyanobacteria.

2. **Evaluate the Options**:
- **Option A: Azolla and BGA (Blue Green Algae)**:
- Azolla is a water fern that has a symbiotic relationship with nitrogen-fixing cyanobacteria (BGA). Both are known to enhance soil fertility and are considered biofertilizers.
- **Option B: Nostoc and Legume**:
- Nostoc is a type of cyanobacteria that can fix nitrogen, but legumes themselves are not biofertilizers; rather, they often host nitrogen-fixing bacteria like Rhizobium in their root nodules.
- **Option C: Rhizobium and Grasses**:
- Rhizobium is a nitrogen-fixing bacterium that forms symbiotic relationships with legumes, not grasses. Grasses do not typically host Rhizobium.
- **Option D: Salmonella and E. coli**:
- Both Salmonella and E. coli are types of bacteria, but they are not used as biofertilizers. In fact, Salmonella is pathogenic.

3. **Conclusion**:
After evaluating all the options, the only correct pair of biofertilizers is **Option A: Azolla and BGA (Blue Green Algae)**.

### Final Answer:
**Option A: Azolla and BGA (Blue Green Algae)**.

---