Which is more important in the prophase of mitosis, that the chromatid pairs become visible, or the nuclear membrane disappears?

  that the chromatid pairs become visible

Mitosis occurs when the nucleus of the cell divides into two identical nuclei, each with the same type and number of chromosomes. The cell's DNA is duplicated during this phase. Sometimes the cell's DNA isn't copied properly resulting in cancer-type cells. 2. Cytokinesis is when the cytoplasm divides into two identical daughter cells. Each cell is genetically identical and both are a similar size. 

C. a mature ovule of a plant.