During which stage of mitosis do chromosomes become visible, the nuclear envelope dissolves, and the spindle forms?

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

Answer: (B)

This question tests the order of mitosis stages by focusing on when chromosomes first become visible and the nucleus breaks down. Chromosomes condense from diffuse chromatin into visible structures during prophase, making them detectable under a light microscope. At the same time, the nuclear envelope dissolves, allowing spindle fibers to form and interact with chromosomes as the spindle apparatus begins to assemble. In later stages, the features change: metaphase has chromosomes aligned in the center with a mature spindle; anaphase pulls sister chromatids apart toward opposite poles; and telophase re-forms the nuclear envelope and chromosomes de-condense. So the described events occur during prophase.