Practice question

Germline derives exclusively from continuous P lineage through sequential asymmetric divisions preserving totipotency. P0 divides into AB and P1, P1 into EMS and P2, P2 into C and P3, P3 into D and P4. P4, the smallest blastomere at 24-cell stage, divides symmetrically into Z2 and Z3 primordial germ cells quiescent until larval feeding. P-granules, maternally deposited ribonucleoprotein complexes containing GLH helicases and PGL scaffold, segregate into P cells, repress somatic transcription via PIE-1 inhibition of P-TEFb, maintaining germ potential throughout embryogenesis.