Question

Which describes a promoter? the first part of an operon that regulates where, when, and to what level a gene is expressed the part of an operon that, if attached by a repressor protein, suppresses the expression of a gene a cluster of genes that are expressed or repressed as a group an enzyme that helps DNA unzip prior to transcription

Answer 1

The question is confusing and only the first part if clear.

The relevance of the second sentence is not clear.

As far as the first question is concerned, promoter is a region in DNA that allows the binding of DNA to RNA polymerase.

This process takes place in case of both prokaryotes and eukaryotes.