Answer: Option B
:
B
Metagenesis is basically the alternation of generations between sexual and asexual reproduction. In other words,a generation developed by sexual means is followed by one or more that reproduce asexually.Many cnidarians exhibit this. Based on this, cnidarians exhibit two basic body forms - the asexual polyp and sexual medusa. Many cnidarians are restricted to one of these types throughout their life. For example, Hydra is found in the polyp form, while the jellyfish (Aurelia) is found in the medusa form. Others, such as Obelia, exhibit both the forms during their life cycle, and thus, such cnidarians are the ones that exhibit metagenesis, as they keep alternating between the polyp and medusa stages.