Molecular biology is concerned with the study of . . . . . .

Which nitrogenous base is $NOT$ present in $DNA$?

What does $Z$ represent in the given figure?

Describe the double helix structure of $DNA$ and explain how the sequences of the other strand are predicted.

The smallest structure having the power of replicating itself is:

$S$ Statement: $DNA$ is inherited by organisms produced by parents.
$R$ Reason: $DNA$ acts as a gene.
$(a)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(b)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(c)$ $S$ is true and $R$ is false.
$(d)$ $S$ is false and $R$ is true.
$(e)$ Both $S$ and $R$ are false.