35.Which one of the following never occurs during mitotic cell division? A. Movement of centrioles towards opposite poles B. Pairing of Homologous chromosomes C. Coiling and condensation of the chromatids D. Spindle fibres attach to kinetochores of Chromosomes
Option B During prophase, the parent cell chromosomes — which were duplicated, condense and become thousands of times more compact than they were during interphase. Because each duplicated chromosome consists of two identical sister chromatids joined at a point called the centromere, these structures now appear as X-shaped bodies. The mitotic spindle also begins to develop during prophase. As the cell's two centrosomes move toward opposite poles. Crossing over, or recombination is the exchange of chromosome segments between non-sister chromatids in meiosis. Crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity. So the answer is 'Crossing over'.
