Identify the correct statement .

Options

A. Arrangement of microtubule in centriole is 9+3.
B. The fimbriae are elongated tubular structures made of a special protein.
C. Structure of chromosomes can be best studied at metaphase .
D. Heterochromatin is genetically more active chromatin.

Answer

To solve the question "Identify the correct statement," we will analyze each of the given statements one by one.

### Step-by-Step Solution:

1. **Evaluate Statement A**: "Arrangement of microtubule in centriole is 9 plus 3."
- **Analysis**: The correct arrangement of microtubules in a centriole is 9 triplets (9+0) in a circular pattern, not 9+3. Therefore, this statement is **incorrect**.

2. **Evaluate Statement B**: "Fimbri are elongated tubular structures made up of a special protein."
- **Analysis**: Fimbriae are actually small, bristle-like structures that protrude from the surface of some bacteria. They are primarily involved in adhesion to surfaces, not elongated tubular structures. Thus, this statement is also **incorrect**.

3. **Evaluate Statement C**: "Structure of chromosomes can be best studied at metaphase."
- **Analysis**: During metaphase, chromosomes are aligned at the equatorial plane of the cell, making them highly condensed and clearly visible under a microscope. This allows for the best study of their structure. Therefore, this statement is **correct**.

4. **Evaluate Statement D**: "Heterochromatin is generally more active than the chromatin."
- **Analysis**: This statement is incorrect because euchromatin is the form of chromatin that is more active in transcription, while heterochromatin is generally more condensed and less active. Therefore, this statement is **incorrect**.

### Conclusion:
The only correct statement among the options provided is **Statement C**: "Structure of chromosomes can be best studied at metaphase."