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Question #47542
The Question
A botanist is comparing the life cycle of a homosporous fern (Pteridophyte) with that of Commelina, an angiosperm known to produce cleistogamous flowers. Which of the following statements regarding their evolutionary and structural differences is INCORRECT?
Options
- A.
The fern prothallus is an inconspicuous, free-living, mostly photosynthetic thalloid gametophyte, whereas the gametophytes of Commelina are highly reduced and endoparasitic on the sporophyte.
- B.
The geographical spread of the fern is restricted due to the requirement of water for fertilization, whereas cleistogamy in Commelina ensures assured seed set even in the absence of pollinators and external water.
- C.
In the fern, the gametophyte develops ex-situ from a haploid spore, whereas in Commelina, the female gametophyte develops in-situ within the megasporangium via sequential meiotic divisions of the functional megaspore.
- D.
The evolutionary trend from the fern to Commelina demonstrates a progressive reduction in the size and independence of the gametophytic generation, coupled with increased sporophytic dominance.
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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
Prothallus|Archegonium|Antheridium|Water_dependence
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The trap relies on 'Process Sequence' and 'Cell Division Type'.
Students often conflate Megasporogenesis (which uses meiosis to create the megaspore) with Megagametogenesis (which uses mitosis to develop the embryo sac from the megaspore).
In a dense, evolution-focused question, the brain easily glosses over the word 'meiotic' when describing gametophyte development.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Kingdom - Class 11 |
| Concept | Pteridophyte Prothallus Nature |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |