Cyanobacteria is found in association with

Options

A. Coralloid roots of Pinus
B. Mycorrhizal roots of Pinus
C. Coralloid roots of Cycas
D. Mycorrhizal roots of Cycas

Answer

To solve the question regarding the association of cyanobacteria, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cyanobacteria**:
- Cyanobacteria, commonly known as blue-green algae, are photosynthetic bacteria that can fix nitrogen from the atmosphere.

2. **Identifying Plant Associations**:
- Cyanobacteria are known to form symbiotic relationships with certain plants. One of the most notable associations is with the coralloid roots of cycads.

3. **Cycads and Coralloid Roots**:
- Cycads are a group of seed plants that have a long fossil history. They are characterized by their coralloid roots, which are specialized structures that house cyanobacteria.

4. **Nitrogen Fixation**:
- The cyanobacteria in the coralloid roots perform nitrogen fixation, converting atmospheric nitrogen into forms that are usable by the plant, such as amino acids.

5. **Conclusion**:
- Based on the information, we can conclude that cyanobacteria are found in association with the coralloid roots of cycads.

### Final Answer:
Cyanobacteria is found in association with the coralloid roots of Cycas.

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