In the $lac$ operon,which enzyme$(s)$ will be produced in the cell if there is a nonsense mutation in the $lac$ $y$ gene?

Select the two correct statements out of the four $(i-iv)$ statements given below about the lac operon.
$(i)$ Glucose or galactose may bind with the repressor and inactivate it.
$(ii)$ In the absence of lactose,the repressor binds with the operator region.
$(iii)$ The $z$-gene codes for permease.
$(iv)$ This was elucidated by Francois Jacob and Jacques Monod.
The correct statements are:

In prokaryotic $DNA$,the recognition of the promoter region by $RNA$ polymerase is determined in some cases by the interaction of certain proteins with which sequences?

What does '$2$' represent in the given figure?

What is an operon?

In the lactose operon of $Escherichia \text{ } coli$, what is the function of the promoter?