The number of complementary hydrogen bond$(s)$ between a guanine and cytosine pair is

Which of the following bases are present both in $DNA$ and $RNA$?

Hydrolysis of which of the following nucleic acids does not give an equal number of $A$ and $T$ or $G$ and $C$?
$(A)$ $m$-$RNA$
$(B)$ Single strand $DNA$
$(C)$ $r$-$RNA$
$(D)$ Double helix $DNA$

Who proposed the double-helix structure of $DNA$?

The number of hydrogen bonds between guanine and cytosine; and between adenine and thymine in $DNA$ is

The $AT/GC$ ratio in human beings is (where $A = \text{adenine}$,$T = \text{thymine}$,$G = \text{guanine}$,$C = \text{cytosine}$)