How many types of histone proteins take part in the composition of a chromosome?

In which of the following is the split-gene arrangement found?

The arrangement of nucleotides in $DNA$ can be seen by which of the following techniques?

Which one of the following nitrogenous bases is $NOT$ a component of $RNA$?

In an experiment,$DNA$ is treated with a compound that intercalates between the stacks of nitrogenous base pairs. As a result,the distance between two consecutive base pairs increases from $0.34 \, nm$ to $0.44 \, nm$. Calculate the length of the $DNA$ double helix (which has $2 \times 10^9 \, bp$) in the presence of a saturating amount of this compound. (in $m$)

The length of $DNA$ in $E. coli$ is . . . . . . .