Which of the following nitrogen bases of nucleic acids is derived from purine?

In nucleic acids,the sequence of the backbone components is

In the $DNA$ of $E. coli$,the mole ratio of adenine to cytosine is $0.7$. If the number of moles of adenine in the $DNA$ is $350000$,the number of moles of guanine is equal to:

Which of the following is/are correct?

The function of $DNA$ in an organism is

For a double strand $DNA$,one strand is given below:
$5'-A-G-T-C-A-C-G-T-A-A-G-T-C-3'$
The amount of energy required to split the double strand $DNA$ into two single strands is $.... \ kcal \ mol^{-1}$.
[Given: Average energy per $H$-bond for $A-T$ base pair $= 1.0 \ kcal \ mol^{-1}$,$G-C$ base pair $= 1.5 \ kcal \ mol^{-1}$. Ignore electrostatic repulsion between the phosphate groups.]