What is the main event during the G₂ phase of the cell cycle?

During the G₂ phase of the cell cycle, the primary focus is on preparing the cell for mitosis, which includes organelle duplication and the synthesis of proteins essential for cell division. This phase follows the S phase, where DNA replication occurs, and leads up to mitosis.

During G₂, the cell ensures that it has all the necessary components to support the division process, such as duplicating organelles and producing energy. This preparation is crucial for the cell to progress into mitosis smoothly and efficiently, ensuring that each daughter cell receives the appropriate number of organelles and resources needed for their function.

In contrast, the other answers describe events that occur at different stages of the cell cycle: chromatin condensation happens in prophase of mitosis, chromosome alignment occurs during metaphase, and the cleavage furrow formation is a characteristic of cytokinesis, which is the final stage of cell division following mitosis. Each of these events is critical but takes place at specific points in the process of cell division, rather than during the G₂ phase.