In a nucleoside,the base is attached to which position of the sugar molecule?

$A$ gene is a segment of a molecule of

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 $DNA$

The structure of the nitrogen-containing heterocyclic base given below represents:

What is the unit consisting of a base,sugar,and phosphate in nucleic acids called?

Explain the structure of nucleic acids.