Final answer:
During telophase of mitosis, the event that occurs is the reformation of nuclear envelopes around the chromosomes, preparing the cell to form two distinct nuclei.
Step-by-step explanation:
During telophase of mitosis, the separated chromosomes arrive at opposite poles of the cell, and one of the key events is the reformation of nuclear envelopes around these chromosomes. This marks the beginning of the end of mitosis as the cells prepare to split into two daughter cells with identical genetic material.
The chromosomes also begin to decondense, transitioning back into a less visible chromatin configuration within the new nuclei. While these events are unfolding, the cell machinery is also preparing for cytokinesis, which is the actual division of the cell's cytoplasm into two distinct daughter cells.