Answer:
Gen lac z: codifies the enzyme β-galactosidase, that hydrolyzes lactose in glucose and galactose.
The other two structural genes are lacy, which is a permease that helps to transfer lactose into the cell. Finally, lacA is a trans-acetylase.
Also, the operon counts with a promoter, that is the region recognized by the RNA polymerase. An Operator region, that is recognized by the LacI repressor, and the repressor gen lacL.