Which one of the following pair is a purine pair?

Information flow or central dogma of modern biology is

Uridine monophosphate is found in

Which of the following is not correct

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.