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

Which of the following is the substrate for $\beta$-galactosidase?

$A$ gene that is responsible for the synthesis of a polypeptide chain is called a .......

The lactose present in the growth medium of bacteria is transported to the cell by the action of

In the $lac$ operon model,to which site does the repressor protein bind?

Assertion $(A):$ Regulation of $lac$ operon by repressor is referred to as negative regulation.
Reason $(R):$ Repressor protein binds to the operator region and prevents $\text{RNA}$ polymerase from transcribing the operon.