Which statement about operons is false?
a) the structural genes in the operon are either all on or all off at a given time.
b) they consist of a cluster of genes with a single promoter.
c) their dna is transcribed into a single molecule of mrna.
d) they are the units of transcriptional regulation in prokaryotes.
e) a repressible operon is turned off unless needed.

All the statement are correct.

Explanation:

In prokaryotes, an operon are unit of transcription regulation, operon are functioning unit of DNA of which consists of cluster of related genes with a single promoter and an operator.

The structural genes in the operon are either all ON or OFF at the same time, because they are controlled by a single promoter and an operator. Represible or inducible operon are all turned of off unless needed.

The DNA of an operon are generally transcribed into a single mRNA molecule which is polycistronic that codes for more than one protein

1. is geographic distribution

2 is increasing complexity

3 is transitional forms