metagenesis is defined as the alternation of generation between asexual and sexual phases of an organism . This phenomenon is a characteristic feature of certain cnidarians (Coelenterates), such as Obelia, where the polyp form produces medusae asexually, and the medusae subsequently produce polyps through sexual reproduction . This specific definition has been tested in previous medical entrance examinations, such as the RE-AIPMT 2015 .