Transposons can be used in which of the following processes?

In the $lac$ operon,the $lac$ $mRNA$:

Who provided the clear explanation of the $Lac$ operon?

An organism is able to survive on a culture medium containing nutrient $A$ through an enzyme-catalyzed process: $A \xrightarrow{X} B \xrightarrow{Y} C$. $A$ mutant organism fails to survive on this medium. However,it grows when nutrient $B$ is added to the medium. Which gene of this mutant is defective?

Given below is the representation of the $lac$ operon of $E. coli$. Identify $I$ and $II$ from the options given below.

$I$

Promoter

$II$

$Z$

$Y$

$A$

Given below are two statements:
Statement $I$: In lac operon,the repressor protein binds to the promoter region of the operon and prevents $\text{RNA}$ polymerase from transcribing the operon.
Statement $II$: Regulation of lac operon can also be visualized as regulation of enzyme synthesis by its substrate.
In the light of the above statements,choose the correct answer from the options given below: