Question

in eukaryotes, what allows only certain genes to be expressed in certain types of cells?

the set of mediator proteins
the set of histone and non - histone proteins
the set of regulatory transcription factors
the set of basal transcription factors

Explanation:

In eukaryotes, cell - type - specific gene expression is mainly regulated by regulatory transcription factors. Regulatory transcription factors can bind to specific DNA sequences (such as enhancers or silencers) and interact with the transcriptional machinery to either activate or repress the transcription of specific genes. Different cell types have different sets of regulatory transcription factors, which determine which genes are expressed. Mediator proteins are involved in the general transcriptional process, histone and non - histone proteins are more related to chromatin structure and general gene accessibility, and basal transcription factors are required for the basic transcription process in all cells.

Answer:

the set of regulatory transcription factors