Assertion : The fimbriae are elongated tubular structures made of a special protein.
Reason : The pili are small bristle like fibres sprouting out of the cell.

Options

A. If both assertion and reason are true amnd reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Explanation

To analyze the given assertion and reason, we can break down the information step by step:

### Step 1: Understanding the Assertion
- **Assertion**: "The fimbriae are elongated tubular structures made of a special protein."
- **Explanation**: Fimbriae are indeed hair-like structures found on the surface of many bacteria. They are primarily composed of a protein called pilin and serve various functions, including attachment to surfaces.

### Step 2: Understanding the Reason
- **Reason**: "The pili are small bristle-like fibers sprouting out of the cell."
- **Explanation**: Pili (singular: pilus) are also hair-like structures, but they are typically longer and fewer in number compared to fimbriae. They can be involved in conjugation (transfer of genetic material between bacteria) and attachment.

### Step 3: Evaluating the Relationship
- Both statements describe structures that are important for bacterial attachment and interaction with their environment.
- However, the assertion describes fimbriae correctly, while the reason describes pili, which is also accurate but does not directly support the assertion.

### Step 4: Conclusion
- Since the assertion is true and the reason is true but does not support the assertion, we conclude that the relationship between the two is not valid. Therefore, both the assertion and the reason are true, but the reason does not explain the assertion.

### Final Answer
- The assertion is true, and the reason is true, but the reason does not support the assertion.

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