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Question #47575
The Question
In Periplaneta americana, the shift towards uricotelism is a critical adaptation for terrestrial survival. Which of the following physiological mechanisms allows its decentralized Malpighian tubules to efficiently eliminate nitrogenous waste while bypassing the need for a high-pressure renal ultrafiltration system characteristic of vertebrates?
Options
- A.
Active secretion of potassium urate from the haemolymph into the tubules, followed by uric acid precipitation and extensive water reabsorption in the rectum.
- B.
High-pressure ultrafiltration of haemolymph across the tubule epithelium, driven by the neurogenic heart, to form a dilute primary urine.
- C.
Passive diffusion of pre-synthesized uric acid from the fat bodies directly into the hindgut, bypassing the midgut entirely.
- D.
Active absorption of ammonia by the glandular cells of the tubules, followed by its conversion into uric acid exclusively within the rectal pads.
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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
Animal Kingdom|Diploblastic Exception|Epithelial Junctions Polarity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often erroneously project the vertebrate mechanism of 'high-pressure ultrafiltration followed by reabsorption' onto invertebrates.
The trap lies in failing to recognize that an open circulatory system (haemocoel) cannot generate high filtration pressures, necessitating an evolutionary shift to an 'active secretion and precipitation' model to achieve water-efficient uricotelism.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Level of Organization vs. Germ Layers |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |