Mutations which alter nucleotide sequence within a gene are called

$A$ : $5S$ $rRNA$ and surrounding protein complex provides binding site of $tRNA$.
$R$ : $tRNA$ is soluble $RNA$ with unusual bases.

Assertion : Histones are basic proteins of major importance in packaging of eukaryotic $DNA$. $DNA$ and histones comprise chromatin forming the bulk of eukaryotic chromosome.
Reason : Histones are of five major types $H_1, H_2A, H_2B, H_3$ and $H_4$.

Match the scientist of Column $I$ with their contributions in Column $II$.

Column $I$	Column $II$
$A$. Griffith	$i$. Lac operon
$B$. Jacob and Monod	$ii$. $DNA$ is the genetic material
$C$. Meselson and Stahl	$iii$. Transforming principle
$D$. Hershey and Chase	$iv$. $DNA$ replicates semiconservatively

$Escherichia \ coli$ is an important material for genetic experiments because

Match the enzyme in Column $I$ with its role in Column $II$:

Column $I$	Column $II$
$1$. Ligase	$a$. Peptide bond formation
$2$. Ribozyme	$b$. Hydrolysis of lactose
$3$. Permease	$c$. Joining of Okazaki fragments
$4$. $\beta$-galactosidase	$d$. Increases permeability

Choose the correct answer from the following options.