Why are histone proteins positively charged?

Who provided the $X-ray$ diffraction data for $DNA$?

$S$ Statement: $DNA$ is inherited by organisms produced by parents.
$R$ Reason: $DNA$ acts as a gene.
$(a)$ Both $S$ and $R$ are true,and $R$ is the correct explanation of $S$.
$(b)$ Both $S$ and $R$ are true,but $R$ is not the correct explanation of $S$.
$(c)$ $S$ is true and $R$ is false.
$(d)$ $S$ is false and $R$ is true.
$(e)$ Both $S$ and $R$ are false.

Chargaff's rules are applicable to

$DNA$ differs from $RNA$ in:

$DNA$ contains