Final answer:
In prophase, chromosomes condense and the nuclear envelope breaks down. In telophase, chromosomes decondense and the nuclear envelope reforms.
Step-by-step explanation:
Prophase:
- Chromosomes condense and become visible.
- Nuclear envelope breaks down.
Telophase:
- Chromosomes decondense and become invisible.
- Nuclear envelope reforms.
Learn more about Mitosis cell division