The labels for ten bacterial strains were mixed up and now you do not know the identity of each strain. you know all strains are auxotrophs and each one has a single, unique mutation. you set up pairwise crosses between bacterial strains and select for exconjugants by plating on mm. use the information below to determine f-, f+, and hfr strains. (- means no colonies grow on mm after conjugation, + means few colonies, +++ means many colonies) explain why f- strains: a1, a2, b5 f+ strains: a3, a4, b3, b4 and hfr strains: b1, b2, a5 b1b2b3b4b5 a1- a2- + + +++ f- strains: f+ strains: hfr strains: