Before the mitosis process (where cells multiply creating two new daughter cells from a single cell) chromosomes are replicated and remain attached to their replicates, then they are condensed forming microtubules as they align on the metaphase plate. <em>Now the sister chromatids (replicates) begin to separate to the opposite poles due to the action of the spindle in </em><u><em>anaphase</em></u> (You can observe this in the image I added). Then telophase begins when the nuclear envelope forms back again and chromosomes begin to unroll.
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The child would possibly still be considered as tall because the tall genes is Dominant, and the only way that recessive allele is selected is when the child receives two recessive allele