The shortest phase of mitosis is .........

Describe the changes observed during the synthesis phase ($S$-phase).

During mitosis,when does the endoplasmic reticulum and nucleolus begin to disappear?

In the given figure,what do $a$ and $b$ represent respectively?

$A$ cluster of minerals that has a star-like shape is called .......

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