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Question #45497
The Question
In certain angiosperms like Citrus, a single seed may contain multiple embryos of varying ploidy levels (n and 2n) alongside a triploid (3n) endosperm. Regarding the origin and developmental dynamics of these embryos, which of the following statements is INCORRECT?
Options
- A.
Diploid embryos that are genetically identical to the maternal plant arise from the nucellus or integuments and protrude into the embryo sac.
- B.
A haploid embryo within the same seed could originate from the parthenogenetic development of a synergid or antipodal cell that failed to degenerate.
- C.
Adventive nucellar embryos derive their nourishment directly from the maternal vascular tissue, leaving the triploid endosperm exclusively for the zygotic embryo.
- D.
The activation of quiescent maternal cells into autonomous embryogenic units creates a competitive environment for endosperm resources, often leading to the developmental arrest of some embryos.
Check Your Answer
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
Embryo Sac Nuclei Count|Polyembryony Mechanisms|Synergid/Antipodal activity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Spatial location and resource allocation in polyembryony.
Students often memorize that nucellar embryos are 'maternal' (sporophytic) but forget the critical NCERT detail that they 'protrude into the embryo sac.' This leads to the misconception that they maintain a separate maternal nutrient supply, missing the advanced concept of intra-seed competition for the endosperm.
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 |