In the Following Schematic Drawings Showing Four Different Network Motifs

Short Answer

In the following schematic drawings showing four different network motifs in gene transcription circuits, indicate whether each of the motifs 1 to 4 corresponds to a feed-forward loop (E), flip-flop device (F), negative feedback loop (N), or positive feedback loop (P). Your answer would be a four-letter string composed of letters E, F, N, or P only, e.g. PNEF.