Suppose that there is a mutation in the lac operon that prevents the repressor from binding to the operator. In the absence of lactose (or allolactose), the genes of the operon will be . In the presence of lactose (or allolactose), the genes will be .

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures