Identify the structure shown in the figure.

$DNA$ generally acts as a template for the synthesis of:

An organism of the wild type that does not require any additional growth supplements for nutrition is called a .....

Read the following statements carefully and choose the correct statements.
$(A)$ In a transcription unit,the promoter is located at the $5'$ end of the coding strand.
$(B)$ The single strand $DNA$ having the polarity $5' \rightarrow 3'$ is the template strand.
$(C)$ $RNA$ polymerase binds to the operator during transcription.
$(D)$ Single base $DNA$ differences occurring in humans are called Single Nucleotide Polymorphisms $(SNPs)$.

In sickle-cell anemia,what is the sequence of the defective nitrogen base on the $DNA$ strand that does not act as a template?

Match the researchers in Column-$I$ with their work given in Column-$II$.

Column-$I$	Column-$II$
$i$. Avery,McCarty,and MacLeod	$a$. $DNA$ digested by DNAse inhibits transformation of $R$ cells to $S$ cells.
$ii$. Griffith	$b$. $DNA$ replication is semi-conservative.
$iii$. Hershey and Chase	$c$. Used Streptococcus pneumoniae.
$iv$. Meselson and Stahl	$d$. Used radioactive Sulphur and Phosphorus.

Select the correct option from the following.