Fertilization and life cycles Transitional Reasoning Practice

Questions

1. 1.

   Biologists studying a newly discovered marine alga observe that it alternates between two distinct, free-living multicellular forms. Form X possesses a haploid chromosome count ($n$) and produces flagellated gametes through mitosis, while Form Y possesses a diploid chromosome count ($2n$) and produces walled spores through meiosis. Based on these findings, which conclusion correctly characterizes the roles of fertilization and meiosis in this organism's life cycle?

   • A) Meiosis directly generates the gametes required for fertilization, while Form X represents the sporophyte phase.
   • B) Form X functions as a gametophyte generation, and fertilization restores the diploid chromosome number that defines Form Y.
   • C) Fertilization occurs through the fusion of haploid spores, giving rise directly to the multicellular haploid generation.
   • D) Form Y develops via mitotic divisions of a haploid spore, bypassing the requirement for gametic fusion.

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