Which stage of mitosis is characterized by the complete disintegration of the nuclear envelope?

Step-by-step solution

The complete disintegration of the nuclear envelope marks the start of the second phase of mitosis , hence the chromosomes are spread through the cytoplasm of the cell. By this stage, condensation of chromosomes is completed and they can be observed clearly under the microscope. This then, is the stage at which morphology of chromosomes is most easily studied. At this stage, metaphase chromosome is made up of two sister chromatids, which are held together by the centromere.