THE CORRECT ANSWER IS B. THE QUESTION ASKS US TO INFER FROM THE PA...
27. The correct answer is B.
The question asks us to infer from the passage the reason that the
replica plating method is effective. The plating method involved
pressing an agar culture on velvet and then transferring that culture
to a new agar plate. The resulting pattern of mutant bacteria
matched the pattern on the original culture. The author concludes
that this indicates that the mutations were already present in the
original culture. We can deduce from this that no new mutant
bacteria developed after the transfer. Otherwise, the plating
technique would not be conclusive. This is consistent with Choice B.