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Question #46694
The Question
In an experimental setup, a researcher partially occludes the thoracic and abdominal spiracles of a late-instar male Periplaneta americana nymph, inducing chronic systemic hypoxia without causing immediate death. Which of the following is the most likely downstream morphological consequence of this respiratory deficit, and what is its physiological basis?
Options
- A.
Arrested development of unjointed, thread-like structures on the 9th sternite, due to hypoxia-induced suppression of the corpora allata and subsequent endocrine failure.
- B.
Failure to develop jointed, filamentous structures on the 10th tergite, because the tracheal system directly oxygenates the gonapophyses.
- C.
Premature formation of the brood pouch from the 7th, 8th, and 9th sternites, due to the accumulation of metabolic acids in the hemolymph.
- D.
Degeneration of the phallic gland, as the respiratory pigment in the hemolymph fails to transport sufficient oxygen to the male reproductive tract.
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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
Cockroach Respiratory Tracheal System|Cockroach Reproductive Dimorphism
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question synthesizes three distinct NCERT concepts: (1) The mechanism of direct tracheal respiration versus pigment-based transport (the 'hemolymph' trap), (2) The precise anatomical distinction between male-specific anal styles (9th sternite) and non-dimorphic anal cerci (10th tergite), and (3) The physiological principle that systemic hypoxia arrests energy-intensive endocrine functions required for sexual maturation.
Students frequently confuse the locations of styles vs. cerci and often forget that insect hemolymph plays no role in respiratory gas transport.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Structural Organisation in Animals - Class 11 |
| Concept | Cockroach Reproductive Dimorphism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |