MCQ Detailed View

In biology, the life cycle of an organism refers to the series of stages it passes through from one generation to the next. Many plants and some simple organisms have two main phases in their life cycle: haploid (n) and diploid (2n). These terms describe the number of sets of chromosomes in their cells.

In mosses, which are non-vascular plants belonging to the group Bryophytes, the haploid phase is dominant. This means that for most of their life, moss plants have cells containing a single set of chromosomes. The green, leafy moss plant we commonly see is actually the gametophyte generation, which is haploid. These gametophytes produce gametes (sperm and eggs) by mitosis. When gametes fuse during fertilization, they form a diploid zygote, which develops into a small, short-lived sporophyte. The sporophyte produces spores by meiosis, which are haploid again, continuing the cycle.

Other options in the question are not correct:

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  Bacteria are prokaryotic organisms with a single circular chromosome, but they reproduce asexually and are not described in terms of haploid-diploid dominance like plants.

  
  


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  Protozoa are mostly unicellular eukaryotes that can have haploid or diploid stages, but their life cycle does not show a clear dominant haploid phase like mosses.

  
  


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  None is incorrect because mosses are a clear example of haploid dominance.

  
  

This dominance of the haploid phase in mosses is an important concept in plant biology and evolution, as it shows how early plants reproduced and adapted to life on land before the evolution of vascular plants, which have a dominant diploid phase.

Thus, the correct answer is Mosses (Option A).