Mutations in bacteria that affect gene regulation may have a cis- or trans-effect on the expression of the protein-encoding genes in an operon? how would the following mutations affect the expression of the lac operon? assume there could be more than one lac operon in the cell and that no glucose is present.

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.