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Question #45498
The Question
A typical angiosperm species possesses 10 linkage groups. Which of the following statements accurately describes the genetic composition of its mature, unfertilized Polygonum-type embryo sac?
Options
- A.
The entire embryo sac contains a total of 80 chromosomes, with each of the 8 haploid nuclei independently representing 10 linkage groups.
- B.
The embryo sac represents exactly 8 linkage groups because the functional megaspore undergoes three sequential free-nuclear mitotic divisions.
- C.
The central cell contains 20 linkage groups because it houses two haploid polar nuclei prior to triple fusion.
- D.
The functional megaspore contains 20 chromosomes, which undergo mitosis to distribute 10 chromosomes to each of the 8 nuclei.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Embryo Sac Nuclei Count|Linkage Group Calculation|Crossing Over
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the physical count of nuclei resulting from post-meiotic mitosis (8 nuclei) with the intrinsic genetic map of the species (linkage groups = n).
Furthermore, a common misconception is that linkage groups multiply with ploidy; however, linkage groups represent unique chromosome types, meaning ploidy increases (like in the n+n central cell) do not increase the number of linkage groups, only the copies of them.
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 |