after s phase  (click to select)  appear to share a common centromere. during g1, cells undergo the major portion of their  (click to select)  . during interphase, all eukaryotic cells synthesize large amounts of  (click to select)  . during g2, chromosomes begin to undergo  (click to select)  . the  (click to select)  is a disk-like protein structure found at the point of constriction on the chromosome.