Practice question

Vulval precursor equivalence group spans P3.p-P8.p in ventral hypodermis, maintained by LIN-39 Hox preventing hypodermal fusion during larval stages. In wild type, only P5.p-P7.p receive sufficient LIN-3 EGF from anchor cell during L3 stage to induce vulval fates via Ras-MAPK and BAR-1 Wnt competence. P3.p, P4.p, P8.p receive below-threshold LIN-3 due to distance and are uninduced, adopting tertiary 3° fate, fusing with hyp7 syncytium via EFF-1 fusogen without dividing, becoming part of large hypodermal syncytium, not contributing to vulva, representing default epidermal fate when RTK absent.