Final answer:
In prophase of cell division, chromatin condenses into chromosomes, the nucleolus disappears, centrioles migrate to opposite poles, and the nuclear envelope breaks down.
Step-by-step explanation:
During prophase of cell division in animal cells, several key events take place that prepare the cell for mitosis. Chromatin condenses and becomes visible as chromosomes.
The nucleolus disappears, the nuclear envelope breaks down, and centrioles migrate to opposite poles of the cell. Spindle fibers, made of microtubules, emerge from the centrioles and start to form the mitotic spindle structure that plays a crucial role during cell division.