During cell division, disappearance of nuclear membrane and nucleolus marks the beginning of ..........................

Explanation

**Step-by-Step Solution:**

1. **Understanding Cell Division Phases**: The cell cycle consists of several phases, primarily the M-phase, which includes prophase, metaphase, anaphase, and telophase.

2. **Identifying Key Events**: During cell division, specific events occur in each phase. The disappearance of the nuclear membrane and nucleolus is a significant event.

3. **Locating the Event**: The disappearance of the nuclear membrane and nucleolus occurs during the prophase stage of cell division.

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