The number of $DNA$ molecules in a chromosome at the $G_2$ stage of the cell cycle is:

During which phase of the cell cycle does histone protein synthesis occur in a eukaryotic cell?

Given below are the two statements.
Statement $I$: Replication of $DNA$ occurs in the '$S$' phase of interphase in the cell cycle.
Statement $II$: Replication of $DNA$ takes place only once in the cell cycle.
In the light of above statements,choose the correct answer from the options given below:

Which of the following is true for the $G_0$ phase?
$I.$ It is a quiescent stage.
$II.$ The cell cycle is arrested in this stage.
$III.$ $G_0$ cells do not grow or proliferate,but are metabolically active.
$IV.$ $G_0$ cells divide in response to stimuli.

Which phase of the cell cycle is characterized by $DNA$ replication,synthesis of histones,and the formation of new nucleosomes?

The biosynthetic phase of the cell cycle is .........