MICROANATOMY

Detailed explanation-1: -During prophase, the chromosomes condense, the nucleolus disappears, and the nuclear envelope breaks down.

Detailed explanation-2: -The connection of microtubules to chromosomes is why the nuclear envelope needed to be broken down during prophase. The nuclear envelope would have gotten in the way. The microtubules from opposite ends of a dividing cell connect to the chromosomes during prophase.

Detailed explanation-3: -In order for these processes to occur, the nuclear membrane must be dissolved during the earliest mitotic phase: prophase. During prophase, DNA condenses into chromosomes, the nuclear membrane dissolves, and the chromosomes enter the cytoplasm.