Contrast constitutive genes from inducible genes. Give two examples for each ...?

A constitutive gene is unregulated, which means that its expression level is relatively constant. The expression of a regulated gene varies under different conditions. In bacteria, the regulation of genes oftentimes occurs at the level of transcription by combinations of regulatory proteins and small effector molecules. In addition, gene expression can be regulated at the level of translation or the function of a protein can be regulated after translation is completed.

An inducible gene is a gene whose expression is either responsive to environmental change or dependent on the position in the cell cycle. The rapid activation of gene expression in response to stimuli occurs largely through the regulation of RNA polymerase II-dependent transcription