Which is an arrangement of genes consisting of an operator, a promoter, and a repressor?

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.

answerall of the above;

answer; an inhibitory postsynaptic potential;