$A$ $DNA$ strand is directly involved in the synthesis of the following,except:

Study the given figure of a nucleosome and select the option that correctly identifies the parts $A, B$ and $C$.

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. Monocistronic gene	$I$. Coding sequence
$B$. Polycistronic gene	$II$. Intervening sequence
$C$. Exons	$III$. Mostly prokaryotes
$D$. Introns	$IV$. Mostly eukaryotes

Genetic mutations occur in which of the following?

Given below are two statements:
Statement $I$: Transfer $\text{RNAs}$ and ribosomal $\text{RNA}$ do not interact with $\text{mRNA}$.
Statement $II$: $\text{RNA}$ interference $\text{(RNAi)}$ takes place in all eukaryotic organisms as a method of cellular defence.
In the light of the above statements,choose the most appropriate answer from the options given below.

Select the correct match for $X$ and $Y$:

Column $X$	Column $Y$
$(1)$ Chromosome	$(P)$ Genetic code
$(2)$ $m-RNA$	$(Q)$ Gene
$(3)$ $t-RNA$	$(R)$ Ribosome
$(4)$ $r-RNA$	$(S)$ Anticodon