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Question #47525
The Question
Gymnosperms like Pinus exhibit unique reproductive features, including polyembryony and a haploid endosperm. Which of the following statements regarding megasporogenesis, polyembryony, and genetic variation in Pinus is strictly INCORRECT?
Options
- A.
Cleavage polyembryony results in genetically identical embryos, as they arise from the splitting of a single proembryo formed after a single fertilization event.
- B.
In simple polyembryony, the genetic heterogeneity among the resulting embryos is primarily due to independent pachytene crossing-over events within the single Megaspore Mother Cell (MMC) of that ovule.
- C.
The cells of the female gametophyte (endosperm) in Pinus are genetically identical to the eggs within its archegonia, as both arise via mitosis from the same functional megaspore.
- D.
The high frequency of recombination during microsporogenesis ensures that multiple pollen tubes entering the same ovule carry genetically distinct male gametes.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Gymnosperm Pollination Geometry|Abscisic Acid (ABA) Antagonism|Integument
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the source of genetic variation in simple polyembryony.
Because multiple distinct embryos form, they mistakenly assume multiple meiotic products (megaspores) survived to form different eggs.
The trap relies on failing to recognize that in gymnosperms, all eggs in a single ovule are mitotic clones of a single functional megaspore, making the paternal gametes (pollen) the sole source of genetic variation among the resulting zygotes.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Kingdom - Class 11 |
| Concept | Gymnosperm Pollination Geometry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |