What does the given figure represent?

The proteins encoded by all the structural genes of the $lac$ operon are essential for which process?

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

What is the structural gene equivalent to?

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:

The differentiation of organs and tissues in a developing organism is associated with which of the following?