The centrosome duplicates during the

The period between the end of the division phase and the initiation of $DNA$ replication is called .......

$A$: The duration of the cell cycle varies in different organisms.
$R$: The duration of the cell cycle varies in different types of cells.

In animal cells,during the $S$-phase,$DNA$ replication begins in the nucleus and the centrioles duplicate in the ..........

Which of the following statements are correct for $G_{1}$-phase?
$I.$ It is the last substage of interphase
$II.$ Cell organelles do not increase in number
$III.$ Cell grows in size and content both
$IV.$ It synthesizes $RNAs$,proteins and other biochemicals for cell growth and subsequent replication of $DNA$
Choose the correct option

What is the period between two successive cell divisions called?