In what way do $DNA$ and $RNA$ differ?

The arrangement of nucleotides in $DNA$ can be seen by which of the following techniques?

Which of the following is not found in $DNA$?

$S$ - Statement: $RNA$ contains thymine in its structure.
$R$ - Reason: $DNA$ does not contain thymine in its structure.

The length of $DNA$ having $23$ base pairs is:

In an experiment,$DNA$ is treated with a compound that intercalates between the stacks of nitrogenous base pairs. As a result,the distance between two consecutive base pairs increases from $0.34 \, nm$ to $0.44 \, nm$. Calculate the length of the $DNA$ double helix (which has $2 \times 10^9 \, bp$) in the presence of a saturating amount of this compound. (in $m$)