The element absent in $RNA$ is

Identify $X$ and $Y$

In the $DNA$ molecule,

The figure gives an important concept in the genetic implication of $DNA$. Fill the blanks $A, B$ and $C$.

In an experiment, $DNA$ is treated with a compound which tends to place itself amongst the stacks of nitrogenous base pairs. As a result of this, the  distancebetween two consecutive base increases. from $0.34- 0.44\,nm$ calculate the length of $DNA$ double helix $($ which has $2 \times 10^9\,bP)$ in the presence of saturating amount of this compound.