The first phase of mitosis is prophase. To determine this, you can recall the stages of mitosis and identify which one occurs first. Mitosis is a process of cell division in which a cell duplicates its chromosomes and divides into two identical daughter cells. The stages of mitosis are prophase, metaphase, anaphase, and telophase. Prophase is the initial stage where the chromatin condenses, and the chromosomes become visible. The nuclear membrane also starts to break down during prophase. Therefore, the correct answer is prophase.
