At the end of which phase does the nuclear envelope disappear?

$S$ - Statement: During anaphase,the paired chromatids separate.
$R$ - Reason: During anaphase,the spindle fibers shorten,and the centromere splits.

At the end of which phase is the number of chromosomes at each pole equal to the number of chromosomes in the parent cell?

Identify the given diagram.

Anaphase Promoting Complex $(APC)$ is a protein degradation machinery necessary for proper mitosis of animal cell. If $APC$ is defective in a human cell,which of the following is expected to occur?

During mitosis, the $ER$ and nucleolus begin to disappear at: