Which stage is the first stage of cell division where chromosomes become visible and the nuclear envelope disappears?

• A. Prophase
• B. Metaphase
• C. Telophase
• D. Anaphase

Answer: (A)

The stage being tested is the first phase of mitosis where the chromosomes become visible and the nuclear envelope breaks down. In prophase, chromatin condenses into visible chromosomes under a light microscope, and the nuclear envelope dissolves so spindle fibers can interact with the chromosomes. The nucleolus also disappears as the cell prepares to separate its genetic material. This combination of visible, condensed chromosomes and the breakdown of the nuclear envelope marks the onset of chromosome movement. In the following stage, chromosomes are already condensed and align at the center, the envelope is gone, and spindle fibers pull the chromatids apart later in the process. So prophase is the stage where these two events first occur.