The following events occur during the various phase of the cell cycle. Fill the blanks with suitable answer against each.
(a)Disintegration of nuclear membrane ________.
(b) Appearance of nucleolus _________.
(c) Division of centromere ___________.
(d) Replication of DNA __________.

1. The disintegration of the nuclear envelope starts during prophase and its full disintegration marks the beginning of the second mitosis phase, thus spreading the chromosomes through the cell's cytoplasm.

2. Telophase: The chromosomes that have reached their corresponding poles decondense and lose their individuality at the start of the final phase of mitosis called as telophase. At this phase, nucleolus appears

3. Anaphase: At the onset of anaphase, each chromosome arranged at the metaphase plate is split simultaneously and the two daughter chromatids, now referred to as chromosomes of the future daughter nuclei, begin their migration towards the two opposite poles.

4. S-Phase or Synthesis Phase: The S phase, short for synthesis phase, is a period in the cell cycle during inter phase, between G1 phase and the G2 phase. In this phase DNA synthesis or replication occurs