a. the pairing of homologous chromosomes during prometaphase is called bi-orientation. b. each sister chromatid in a pair must attach to the opposite pole of the spindle for the sister chromatids to be segregated properly. c. attachment of sister chromatid pairs to opposite poles of the spindle creates tension in the kinetochores, which signals that the sister chromatids are ready to be separated. d. the cell-cycle control system monitors the tension on the kinetochores to ensure that anaphase does not occur until the sister chromatids are correctly attached to the spindle.