The figure shows an important concept of $DNA$ implication. Fill in the blanks from $A$ to $C$.

The smallest unit of genetic material which,when altered,results in a mutation is known as .....

What is the correct chronological sequence of the following events?
$1.$ Formation of the chromosome theory of heredity
$2.$ Experiments which proved that $DNA$ is the hereditary material
$3.$ Mendel's laws of inheritance discovery
Code:

The clover leaf model of $tRNA$ consists of:

Match the following and select the correct option:
Column $A$ | Column $B$
$(i)$ Oncogenes | $(1)$ Causes $AIDS$
(ii) Single circular $DNA$ | $(2)$ $Lac$-Operon concept
(iii) Splicing | $(3)$ Component of bacterial chromosome
(iv) Jacob and Monod | $(4)$ Processing of $mRNA$ molecules
| $(5)$ When activated cause cancer
Select the correct sequence for $(i), (ii), (iii), (iv)$ respectively.

How many of the following statements are correct?
$I - RNA$ is formed from $DNA$ by the process of transcription.
$II - DNA$ is more stable than $RNA$.
$III - RNA$ acts as a catalyst (enzyme) in some biochemical reactions.
$IV - DNA$ is resistant to mutations due to its double-helical structure and the presence of complementary strands that allow for repair mechanisms.