What is alternation of generations? Illustrate this phenomenon with life history of Obelia. (IAS 2021/15 Marks Marks)

Alternation of generations
Alternation of generations is a phenomenon commonly observed in the life cycles of many organisms, particularly in plants and certain groups of animals. It involves the alternation between two distinct multicellular forms in the life cycle of an organism - a haploid (n) form and a diploid (2n) form. This phenomenon allows for both sexual and asexual reproduction to occur in the life cycle of the organism. It is also known as metagenesis.
Alternation of Generations in Obelia (Metagenesis in Obelia)
Please refer to 2018 question.
Conclusion
The alternation of generations in the life cycle of Obelia allows for both asexual reproduction through polyps and sexual reproduction through medusae. This phenomenon ensures genetic diversity and the continuation of the species. Studying the life history of Obelia provides valuable insights into the complex and fascinating world of zoology.