In a given strain of bacteria, all of the cells are usually killed when a specific concentration of streptomycin is
present in the medium. Mutations that confer resistance to streptomycin occur. The streptomycin-resistant
mutants are of two types: some can live with or without streptomycin; others cannot survive unless this drug is present in the medium. Given a streptomycin-sensitive strain of this species, outline an experimental procedure by which streptomycin-resistant strains of the two types could be established.