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Question #46156
The Question
In Molluscs, the mantle cavity houses feather-like gills that perform respiratory and excretory functions, while metanephridia handle osmoregulation. Suppose a hypothetical 'ANF-like' (Atrial Natriuretic Factor) signaling pathway, which normally promotes fluid and sodium excretion into the mantle cavity, is completely knocked out due to a mutation. Which of the following physiological crises will the mollusk most likely experience?
Options
- A.
Fluid retention and elevated hydrostatic pressure, mirroring vertebrate hypertension, which impairs metanephridial ultrafiltration.
- B.
Excessive diuresis into the mantle cavity, leading to a drastic drop in hemolymph pressure and hypo-osmotic shock.
- C.
Uninhibited vasodilation of the open circulatory vessels, leading to pooling of hemolymph in the visceral hump.
- D.
Enhanced ultrafiltration in the metanephridia due to a compensatory drop in the localized hydrostatic pressure.
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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
Mantle_Cavity|Nephridia|ANF
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'ANF decreases blood pressure' but fail to invert the logic for a knockout scenario (which causes hypertension and fluid retention).
This question tests the ability to map vertebrate endocrine logic (ANF/RAAS antagonism from 'Excretory Products') onto molluscan anatomy ('Animal Kingdom' - mantle cavity, metanephridia), requiring deep conceptual synthesis of osmoregulatory physics.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Mollusca Mantle Cavity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |