Regrading your question: one cell dividing into 3 cells. It’s actually dividing into 2 cells and not 3 cells, except that one of the daughter cells will have two nuclei instead of one nucleus, hence we call them binucleated cells. If you watch the video carefully, you’ll notice that too. How does it happen? Some cells contain three or more centrioles (these are cylindrical organelles involved in the development of spindle fibres during cell division), resulting in multiple poles. This leads to the cells pulling chromosomes in many directions that end in multiple nuclei found in one cell.
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