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Question #45496
The Question
In a species of Asteraceae exhibiting diplosporous apomixis, the Megaspore Mother Cell (MMC) directly develops into an 8-nucleate, 7-celled embryo sac without undergoing meiosis. Which of the following statements is INCORRECT regarding the cellular ploidy and subsequent development within this ovule?
Options
- A.
The egg cell is unreduced (2n) and develops into an embryo without syngamy, ensuring the progeny is a maternal clone.
- B.
The central cell contains two haploid polar nuclei, ensuring that if pseudogamy occurs, a standard triploid endosperm is formed.
- C.
The antipodal cells and synergids are diploid, possessing the exact genetic constitution of the nucellus.
- D.
This phenomenon represents a form of agamospermy where the transition from sporophyte to gametophyte occurs without a reductional division.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Embryo Sac Nuclei Count|Apomixis Genetics|Megaspore Mother Cell
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' is the rigid association of the 8-nucleate, 7-celled Polygonum-type embryo sac with haploidy.
Students often fail to realize that in diplosporous apomixis, the structural morphology of the embryo sac is conserved, but the ploidy of every individual nucleus is doubled (2n instead of n) because the reductional division (meiosis) was entirely bypassed.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Embryo Sac Nuclei Count |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |