What characteristic of genes would classify them as belonging to the same operon?

The characteristics of genes that would classify them as belonging to the same operon are that they are transcribed as a unit and are under the control of single promotor and single operator.

Therefore operons contain the set of genes that are expressed together. An operon contains single promotor that is responsible for the transcription of all the structural genes present in the operon.

Lac operon contains one promoter, an operator and three structural genes that are Z, Y and A. Operator is responsible for the regulation of transcription of the operon.