Genetic disorder can result when chromtids fail to separate properly. during which phase is this problem most likely to occur?

In general, nondisjunction can occur in any form of cell division that involves ordered distribution of chromosomal material. There are three forms of nondisjunction: failure of a pair of homologous chromosomes to separate in meiosis I, failure of sister chromatids to separate during meiosis II, and
failure of sister chromatids to separate during metaphase going into anaphase of mitosis. so it will be mitosis hanse.