Consider the Following Experiment

question 61

Multiple Choice

Consider the following experiment. First, large populations of two mutant strains of Escherichia coli are mixed, each requiring a different, single amino acid. After plating them onto a minimal medium, 45 colonies grew. Which of the following may explain this result?

• A) The colonies may be due to recombination.
• B) The colonies may be due to back mutation (reversion).
• C) Either A or B is possible.
• D) Neither A nor B is possible.