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Question #46961
The Question
A coastal ecosystem receives excessive agricultural runoff rich in nitrogen and phosphorus, leading to an exponential bloom of bioluminescent, biflagellated organisms that turn the water red. Which of the following statements regarding this ecological cascade is INCORRECT?
Options
- A.
The organisms responsible are dinoflagellates like Gonyaulax, which release toxins that can kill marine animals.
- B.
The mass mortality of aquatic arthropods and fishes in this ecosystem is exclusively caused by the direct neurotoxic effect of the bloom's toxins.
- C.
During the decline phase of this bloom, the Biochemical Oxygen Demand (BOD) of the water body increases significantly due to aerobic decomposers.
- D.
The primary nutrients triggering this bloom represent reservoirs from both gaseous (Nitrogen) and sedimentary (Phosphorus) biogeochemical cycles.
Check Your Answer
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
Chrysophytes Silica Wall|Symbiotic Nitrogen Fixation|Nitrogenous Waste Classification
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often hyper-focus on the 'toxin' aspect of Red Tides (from Biological Classification) and fail to integrate the 'BOD/Hypoxia' mechanics of algal blooms (from Environmental Issues).
The trap uses the absolute word 'exclusively' to test if the student can synthesize multiple ecological stressors (toxins + oxygen depletion) acting simultaneously.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Chrysophytes Silica Wall |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |