Why would lac z gene be fused to coding sequence of chain A and B in plasmids of E.coli?

The sequence of genes in lac operon in E. coli is :

Lac 'Z' gene codes for

The sequence of genes In lac operon in E. coli are :

In which of the following years and companies prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of E.coli to produce insulin chains

In which of the following years and companies prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of E.coli to produce insulin chains

Eli Lilly, an American company, prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in the plasmids of E.coli to produce insulin chains. Chains A and B were produced separately, extracted, and combined by creating

Eli Lilly, an American company, prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in the plasmids of E.coli to produce insulin chains. Chains A and B were produced separately, extracted, and combined by creating

The sequence of structural genes in lac operon is

The sequence of structural genes in lac operon is