Transposons can be used during which one of the following?

Which statement is correct for homeotic genes?

How is gene expression regulated in eukaryotes?

An environmental agent that triggers transcription from an operon is a:

Select two statements out of the four given statements $(i-iv)$ with respect to the $lac$ operon.
$(i)$ Glucose or galactose binds with the repressor and inactivates it.
$(ii)$ In the absence of lactose,the repressor binds with the operator.
$(iii)$ The $Z$-gene codes for permease.
$(iv)$ It was elucidated by Francois Jacob and Jacques Monod.

When does $lac$ operon in $E. coli$ become "switched on"?