Fertilization and life cycles Original Scenario-Based Download PDF

Questions

1. 1.

   While surveying a hidden volcanic cave ecosystem, biologists discover a novel organism, Pyrocystis mirabilis, that exhibits an alternation of generations between two multicellular forms. The researchers note that the delicate haploid leafy form develops gametangia that discharge flagellated cells into droplets of moisture. When these cells meet compatible cells from another individual, they pair and completely merge their contents to form a durable zygote. Which statement accurately identifies this cellular event and its function in the organism's life cycle?

   • A) It represents fertilization, which combines two haploid genomes to restore the diploid ($2n$) state required for the multicellular sporophyte stage.
   • B) It represents meiosis, which reduces the chromosomal complement to establish the haploid ($n$) state required for the multicellular sporophyte stage.
   • C) It represents syngamy, which duplicates maternal DNA without nuclear fusion to sustain the haploid ($n$) gametophyte stage.
   • D) It represents sporogenesis, which stimulates asexual cleavage divisions to preserve the diploid ($2n$) gametophyte stage.