What is the relationship between operons and transcription units?

The transcription of genes in a single mRNA is known as operon and they often identified by the presence of promoters and terminators. Thus, there are several structural genes that are present in operon and they arranged under a common promoter, regulated by common operator. However, the structural gene that lies a promoter sequence provides a site for RNA polymerase to bind and initiate transcription. 

liquid crystals are matters in a state which have properties between those of conventional liquids and those of solid crystals[1]. liquid crystal is partially ordered and anisotropic. in terms of molecular order, liquid crystal molecules have one-dimensional or two-dimensional long - range order.

b brown mice / white sand dunes