The Cytoskeleton of an Animal Cell Changes Markedly Between G₁

The cytoskeleton of an animal cell changes markedly between G₁ and early M phase (prophase) of the cell cycle.For each of the following sentences, choose one of the options enclosed in square brackets that best describes the changes to the cytoskeleton and its components.
Before mitosis, the number of centrosomes must [increase/decrease].At the beginning of [anaphase/prophase] in animal cells, the centrosomes separate in a process driven partly by interactions between the [plus/minus] ends of microtubules arising from the two centrosomes.Centrosome separation initiates the assembly of the bipolar mitotic spindle and is associated with a sudden [increase/decrease] in the dynamic instability of microtubules.[Interpolar/astral/kinetochore] microtubules are formed in an overlap zone where two microtubules from opposite centrosomes interact.During anaphase [A/B], kinetochore microtubules are shortened, dragging chromosomes toward their spindle pole.