[Campbell Biology P.1035] A mammal living in an extremely arid environment relies heavily on ... | Practice Question

A mammal living in an extremely arid environment relies heavily on its kidney function to survive. Based on the information provided, which adaptation in its kidney structure would be most crucial for its survival, and why?

  • A: An increased proportion of cortical nephrons to maximize filtration rate.
  • B: Larger renal arteries to ensure a higher blood flow to the cortex for efficient waste removal.
  • C: A higher density and longer loops of juxtamedullary nephrons to enhance water reabsorption and produce hyperosmotic urine.
  • D: A larger urinary bladder to store more urine, reducing the frequency of urination.

Explanation

The text states: 'Juxtamedullary nephrons are essential for production of urine that is hyperosmotic to body fluids, a key adaptation for water conservation in mammals.' In arid environments, water conservation is paramount. A higher density and longer loops of juxtamedullary nephrons would maximize their ability to reabsorb water, producing highly concentrated urine, which is crucial for survival in water-scarce conditions.