Activators are proteins that bind to regions of DNA and increase the rate of transcription of specific genes. Repressors, on the other hand, are proteins that decrease the transcription of specific genes.

Activators and repressors are examples of factors a cell can use to
A.
replicate DNA sequences.
B.
regulate gene expression.
C.
change the genetic code of an organism.
D.
assemble amino acids into proteins.

B. regulate gene expression.