Before You Begin
Question #45731
The Question
Which of the following statements regarding the osmoregulatory adaptations of terrestrial desert mammals and marine mammals is INCORRECT?
Options
- A.
Desert mammals utilize a high proportion of juxtamedullary nephrons with elongated Loops of Henle to establish a steep cortico-medullary osmotic gradient.
- B.
Marine mammals possess reniculate (multi-lobed) kidneys that facilitate the excretion of urine that is significantly hyperosmotic to seawater.
- C.
In both groups, ADH secretion and collecting duct receptor sensitivity strictly follow a universal linear dependence on acute plasma osmolarity, independent of specific ecological pressures.
- D.
Despite their aquatic environment, marine mammals face continuous dehydration stress and exhibit an evolutionarily heightened basal sensitivity to ADH for continuous facultative water reabsorption.
Check Your Answer
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
Loop of Henle|Medullary Gradient|Adaptation
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' is the assumption of universal homeostatic set-points.
Students learn the standard NCERT model where osmoreceptors trigger ADH strictly when blood osmolarity rises above normal levels.
The trap assumes this linear tracking is identical across all mammals.
Students fail to realize that evolutionary pressures in marine mammals alter this basal sensitivity, decoupling ADH action from acute plasma osmolarity spikes to ensure constant, maximal water conservation in a hypertonic environment.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | ADH (Vasopressin) Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |