Fertilization and life cycles Original Scenario-Based Practice

Questions

1. 1.

   Explorers researching a subterranean bioluminescent organism, Cryptoglow noctis, discover that its macroscopic, vegetative body is entirely composed of haploid cells containing 8 chromosomes ($n = 8$). During environmental drought, two haploid cells fuse to produce a single-celled, resistant zygote containing 16 chromosomes, which immediately undergoes meiosis upon rehydration to release haploid cells that divide mitotically into new vegetative bodies. Based on this sequence, which statement accurately characterizes the biological processes occurring in the life cycle of Cryptoglow noctis?

   • A) The fusion of gametes represents meiosis that reduces ploidy, whereas the zygote undergoes fertilization to form the haploid vegetative organism.
   • B) Fertilization doubles the chromosome number to form a transient diploid zygote, while meiosis restores the haploid condition characteristic of a haploid-dominant life cycle.
   • C) The single-celled zygote undergoes repeated mitotic divisions to produce a multicellular diploid sporophyte, establishing an alternation of generations.
   • D) Meiosis directly produces haploid gametes from a persistent multicellular diploid body, demonstrating a diploid-dominant life cycle similar to animals.

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