<prompt> Which of the following show regressive metamorphosis?Hydatid cystCysticercoidCysticercus bovisCysticercus cellulosae  <response>: Ans. is a i.e., Hydatid cystRef: D.R. Arora, 3rde, p. 141 Regressive metamorphosis: Sometimes, hydatid cyst containing protoscolices may rupture in intermediate host to release its content in the tissue. If such a patient survives, the released protoscolices may revert to hydatid cyst instead of developing into an adult worm Normally protoscolex give rise to adult worm. 