D: faulting hope i could help
Answer:
The given blank can be filled with operator.
Explanation:
The proteins that assist in turning on or turning off the function of a specific gene by getting combined with certain sections of the DNA are known as transcription factors. The transcription factors that activate the transcription of a specific gene are known as activators, while that prevents transcription and is termed as repressors.
A repressor can be an RNA or a DNA binding protein, which prevents the articulation of genes by getting combined with the operator. A repressor, which binds with DNA prevents RNA polymerase from getting combined with the promoter, which further inhibits the transcription of the genes into mRNA.
The answer is A, 'a mammal' because it goes with the copulative verb 'to be', i. e., 'is'.
Fire can not burn without oxygen
