Detailed Instructions: In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.
Q: Mice lacking Cks2 were sterile because the gametes were unable to progress beyond this stage. Before this can begin, an E3 ubiquitin ligase must be activated which destroys the targets through the 26S proteasome. The degradation of one of those targets, securin, allows separase to breakdown cohesin, which marks the start of this. The cohesins hold together sister chromatids, and, once separated, daughter chromosomes are formed and move towards the spindle poles. For 10 points, give the name of this stage of mitosis, which results in two sets of chromosomes being formed at the poles of the cell and that starts after metaphase.
A:
Science