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Question #46664
The Question
In a terrestrial ecosystem, an environmental anomaly completely inhibits the process of humification during decomposition, while fragmentation and catabolism continue normally. Despite optimal Photosynthetically Active Radiation (PAR) and rainfall, the ecosystem's Gross Primary Productivity (GPP) eventually collapses. Which of the following best explains the primary cause of this systemic failure?
Options
- A.
The absence of humus prevents the immediate release of inorganic nutrients, directly halting the catabolic action of bacterial and fungal enzymes.
- B.
The ecosystem suffers a bottom-up regulatory failure because the loss of colloidal humus eliminates the soil's nutrient reservoir, leading to severe mineral leaching and limitation.
- C.
The Grazing Food Chain (GFC) becomes entirely dependent on the Detritus Food Chain (DFC) for energy flow, which violates the 10 percent law of energy transfer.
- D.
Uninhibited catabolism causes a rapid spike in soil mineralization, creating a toxic hyper-accumulation of inorganic salts that denatures photosynthetic enzymes in producers.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Climax|Pioneer_Species|Invasive_Biotic_Resistance
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often compartmentalize the Grazing Food Chain (GFC) and Detritus Food Chain (DFC) as independent pathways, forgetting that in terrestrial ecosystems, the GFC is strictly dependent on the DFC for nutrient recycling.
The trap lies in assuming that abundant sunlight (PAR) and water guarantee high primary productivity, ignoring the structural necessity of humus as a colloidal nutrient reservoir that prevents leaching.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Productivity Ratios |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |