Interzonal fibers are formed during which stage?

The centromere is required for:

In the cell cycle,during which phase are chromosomes arranged at the equatorial plate?

Which of the following phases is not a part of mitosis?

$A$: The complete disintegration of the nuclear envelope marks the start of metaphase.
$R$: Chromosomes are distinct with two chromatids at this stage.

In cell division, spindle fibers are made up of which protein?