Using mutants 2 and 3 from Problem 19, following mixed infection on E. coli B, progeny viruses were plated in a series of dilutions on both E. coli B and K12 with the following results. What is the recombination frequency between the two mutants? Strain Plated Dilution Plaques E. coli B 10⁻⁵ 2 E. coli K12 10⁻¹ 5