The $DNA$ model was first proposed by .......

Match the following columns:

Column-$I$	Column-$II$
$P$. Bacteriophage $\phi \times 174$	$I$. $5386$ nucleotides
$Q$. Bacteriophage lambda	$II$. $48502 \, bp$
$R$. Escherichia coli	$III$. $3.3 \times 10^9 \, bp$
$S$. Human haploid $DNA$	$IV$. $4.6 \times 10^6 \, bp$

In the $DNA$ molecule,

In a $DNA$ molecule,if the base ratio $(A+T)/(G+C)$ is $0.3$ and the amount of $A+T$ nitrogenous bases is $30,000$,what will be the amount of $G+C$ nitrogenous bases in the $DNA$ (in $,000$)?

Which one of the following is the genetic material of bacteriophage $\phi X 174$?

$A$ genome is the