Which of the following nitrogenous bases is $NOT$ present in $RNA$?

What is the reason for the anti-parallel nature of $DNA$ strands?

The coding sequences of genes are known as . . . . . . .

What would happen if histones were to be mutated and made rich in acidic amino acids such as aspartic acid and glutamic acid in place of basic amino acids such as lysine and arginine?

The function of histone proteins in the nucleus is:

Assertion : In a $DNA$ molecule,$A-T$ rich parts melt before $G-C$ rich parts.
Reason : In between $A$ and $T$ there are three $H-$ bonds,whereas in between $G$ and $C$ there are two $H-$ bonds.