Answer:
Regulatory gene
Explanation:
Transcription is one of the major processes that occurs during gene expression. It is the transfer of the genetic instructions in DNA to mRNA. A strand of mRNA is made using complementary base pairs.
However, there is need for gene expression to be regulated.
Gene regulation refers to the mechanism that acts to induce or repress the expression of a gene. These include structural & chemical changes to the genetic material, binding of proteins to specific DNA elements to regulate transcription. These proteins that influences transcription by binding to specific nucleotide sequences (DNA segments/gene) are referred to as REGULATORY PROTEINS and those involved in regulating transcription of genes are called TRANSCRIPTION FACTORS.
Regulatory proteins controls the rate and manner of gene expression by binding to specific genes, thus, making it easy or hard for RNA polymerase (enzyme that attaches to DNA to synthesize mRNA molecule) to bind to the promoter of that gene.
Transcription factors (regulatory proteins) that promote gene transcription are called ACTIVATORS while those that decrease are called REPRESSORS.
I am not entirely sure what you mean by "responding variable" but I'm going to guess it was the vinegar since it has been used as a perservative for years.
Hope that helps in some way.
L*W*H should be your answer
