In the given diagram of the lac operon,which one is the inducer?

Which statement is correct for homeotic genes?

Which enzyme is the expression product of the $y$ gene in the $lac$-operon?

Match List-$I$ with List-$II$.

List-$I$	List-$II$
$A$. Gene $a$	$I$. $\beta$-galactosidase
$B$. Gene $y$	$II$. Transacetylase
$C$. Gene $i$	$III$. Permease
$D$. Gene $z$	$IV$. Repressor protein

Choose the correct answer from the options given below:

Who proposed the operon model for the first time?

Which of the following statements concerning the regulatory gene $(i)$,associated with the $lac$ operon are incorrect?
$(I.)$ $\text{mRNA}$ is transcribed from the $i$ gene whether lactose is present or not.
$(II.)$ $\text{mRNA}$ is transcribed from the $i$ gene only when the lactose is present.
$(III.)$ $\text{mRNA}$ is transcribed from the $i$ gene only when the lactose is not present.
$(IV.)$ Lactose inhibits the translation of $i$ gene $\text{mRNA}$.