During prophase, the parent cell chromosomes — which were duplicated during S phase — condense and become thousands of times more compact than they were during interphase. ... Cohesin forms rings that hold the sister chromatids together, whereas condensin forms rings that coil the chromosomes into highly compact forms.
See that river on the bottom? That water has been flowing in the canyon for a long time and has slowly been chipping away at the rocks to give what you see today.
B. erosion from the water
A. Atoms with an ironic bonds
