Chromatin fibres are observed only in the

Options

A. Prophase
B. Metaphase
C. Telophase
D. Interphase

Answer

**Step-by-Step Solution:**

1. **Understanding Chromatin Fibers**: Chromatin fibers are the form of DNA that is loosely packed in the nucleus of a cell during interphase. They are not visible as distinct structures during this phase because they are in a relaxed state.

2. **Identifying the Phases of Cell Division**:
- **Interphase**: This is the phase where the cell is not actively dividing. It is a preparatory phase where the cell grows and duplicates its DNA. During this phase, chromatin fibers are present and can be observed as a long network of thin fibers.
- **Prophase**: In this phase, the chromatin fibers condense to form distinct chromosomes. Therefore, chromatin fibers are not observed in their loose form.
- **Metaphase**: The chromosomes line up at the cell's equatorial plane. Again, the chromatin is fully condensed into chromosomes, making it impossible to observe chromatin fibers.
- **Telophase**: The chromosomes begin to de-condense back into chromatin fibers as the cell prepares to divide. However, the distinct chromatin fibers are not observed as they are in interphase.

3. **Conclusion**: Since chromatin fibers are only observed in their loose form during interphase, the correct answer to the question is that chromatin fibers are observed only in the **interphase**.

4. **Final Answer**: The correct option is **interphase (Option 4)**.

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