Which of the following serves a dual purpose in $DNA$ replication?

$DNA$ polymerase enzyme was discovered by:

If $E. coli$ is grown in a $^{15}N$ medium for $80$ minutes,starting from a $^{14}N$ medium,what will be the ratio of light to hybrid $DNA$ molecules obtained?

Match the following columns:

Column-$I$ (Enzyme)	Column-$II$ (Function)
$P$. $DNA$ Polymerase	$I$. Synthesizes $DNA$ strand
$Q$. $DNA$ Helicase	$II$. Breaks $H$-bonds of $DNA$ strands
$R$. $DNA$ Ligase	$III$. Joins $DNA$ fragments

Which bonds does helicase break in $DNA$?

Consider the process that a cell uses to replicate its double strand $DNA$ to make copies for daughter cells. Which statement describes the $DNA$ in daughter cells?