A) Yes,because bacteria require both glucose and lactose.
B) Yes,because it is easier for bacteria to metabolize lactose than glucose.
C) Yes,because three proteins are required for the uptake and metabolism of lactose.
D) No,because lactose metabolism requires an inducer.
E) No,because lactose is broken down into glucose,which is already abundant.

A) A constitutive gene and an activator
B) A transcription factor and a constitutive gene
C) A repressor and an activator
D) A promoter and a repressor
E) A promoter and an activator

A) Presence of $\beta$ -galactoside transacetylase at a high concentration when $\beta$ -galactoside is present at a low concentration
B) Production of $\beta$ -galactoside transacetylase at very low levels in the absence of lactose
C) Production of $\beta$ -galactoside transacetylase at very low levels when glucose is abundant
D) Production of $\beta$ -galactoside transacetylase at high levels when lactose is at a high concentration and glucose is not available
E) Presence of both $\beta$ -galactoside transacetylase and $\beta$ -galactoside in very low concentrations