$A$: $DNA$ replication occurs only once in meiosis.
$R$: Exchange of $DNA$ in chromosomes is seen in mitosis.

Statement $P$: The $G_1$ phase is the final phase of interphase.
Statement $Q$: $DNA$ synthesis occurs in the $G_2$ phase.

Which of the following options represents the correct sequence of events during mitosis?

Match the following columns correctly:

Column-$I$	Column-$II$
$(a)$ Number of cells in an adult human body	$(p)$ $90$ minutes
$(b)$ Average cell cycle duration of a human cell	$(q)$ $10^{14}$
$(c)$ Total sub-phases of Interphase	$(r)$ $24$ hours
$(d)$ Typical cell cycle duration of yeast	$(s)$ $3$

$(1)$ Definition / Explanation: Chiasmata
$(2)$ Definition / Explanation: Syncytium

Which of the following statements are correct?
$a -$ Cell cycle duration can vary from organism to organism and also from cell type to cell type.
$b -$ $DNA$ synthesis occurs only in pachytene.
$c - G_1$ phase corresponds to the interval between mitosis and initiation of $DNA$ replication.