$DNA$ segments that can switch their position are called:

How many hydrogen bonds are present between Guanine and Cytosine?

Histones are rich in

Which of the following statements are correct with reference to the packaging of the $DNA$ helix?
$(A)$ Histones are organized to form a unit of eight molecules called a histone octamer.
$(B)$ Histones are negatively charged basic proteins.
$(C)$ Histones are rich in the basic amino acid residues - lysine and arginine.
$(D)$ The negatively charged $DNA$ is wrapped around the positively charged histone octamer to form a nucleosome.
$(E)$ The packaging of chromatin at higher levels requires an additional set of proteins called non-histone chromosomal proteins.

The Feulgen reaction is specific for:

Which of the following bases is present in $RNA$ instead of $Thymine$ found in $DNA$?