The interphase has highly extended and elaborate nucleoprotein fibres called:-

Answer

**Step-by-Step Solution:**

1. **Understanding Interphase**: Interphase is the phase of the cell cycle when the cell is not dividing. During this time, the cell is preparing for division by growing and duplicating its DNA.

2. **Nucleus and Chromatin**: The nucleus is a vital cell organelle that contains the genetic material. Within the nucleus, the DNA is organized into structures called chromatin.

3. **Definition of Chromatin**: Chromatin consists of nucleoprotein fibers that are highly extended and elaborate. It is the form that DNA takes when the cell is not dividing, allowing for the processes of transcription and replication to occur.

4. **Identification of the Answer**: The question specifically asks for the term used to describe these nucleoprotein fibers during interphase. The correct term is "chromatin."

5. **Additional Structures in the Nucleus**: Besides chromatin, the nucleus also contains a nuclear matrix and one or more spherical bodies known as nucleoli.

**Final Answer**: The interphase has highly extended and elaborate nucleoprotein fibers called **chromatin**.

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