What happens during the metaphase of mitosis?

During the metaphase of mitosis, chromosomes align in the middle of the cell, also known as the metaphase plate. This precise positioning is crucial for the equal distribution of chromosomes to the daughter cells. Mitosis involves several stages, and metaphase specifically follows prophase, during which chromosomes condense and become visible. This alignment ensures that each daughter cell receives one copy of each chromosome, preventing genetic imbalances.

The correctness of the answer lies in understanding the orderly progression of mitosis. During metaphase, the chromosomes have already formed and condensed, making option "A" partially accurate but not representative of the unique action occurring specifically in metaphase. Options regarding the division of the nucleus or a resting cell state pertain to other phases or conditions, such as telophase or interphase, respectively, where the cell is not actively dividing. Therefore, the pivotal action in metaphase is indeed the precise alignment of chromosomes at the cell’s equator, which is essential for the subsequent stage of mitosis, anaphase.