Which of the following statements best defines the term operon?
An operon is a region of DNA that codes for sugar-metabolizing enzymes.
An operon is a region of DNA that consists of a single gene regulated by more than one promoter.
An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter.
An operon is a region of RNA that consists of the coding regions of more than one gene.