Final answer:
Prophase can be broken into substages including nuclear envelope breakdown, chromatin condensation, centrosome migration, and spindle formation.
Step-by-step explanation:
In mitosis, prophase is the first phase and can be further divided into substages. The substages of prophase are:
- Nuclear envelope breakdown: The nuclear envelope starts to break into small vesicles.
- Chromatin condensation: The loosely packed chromatin coils and condenses into visible chromosomes.
- Centrosome migration: The centrosomes begin to move to opposite poles of the cell.
- Spindle formation: The microtubules that form the mitotic spindle extend between the centrosomes.
These substages occur sequentially during prophase.