[Campbell Biology P.1040] Which of the following statements correctly compares the kidney ada... | Practice Question

Which of the following statements correctly compares the kidney adaptations of desert, aquatic, and terrestrial mammals?

  • A: Desert mammals have long loops of Henle to produce highly concentrated urine, while aquatic mammals have mostly cortical nephrons and a lower ability to concentrate urine.
  • B: Aquatic mammals typically have longer loops of Henle than desert mammals, allowing them to excrete excess water more efficiently.
  • C: Terrestrial mammals living in moist conditions have the longest loops of Henle among all mammals, indicating their superior ability to conserve water.
  • D: All mammals possess juxtamedullary nephrons with loops of Henle that extend equally deep into the medulla, ensuring uniform urine concentration across species.

Explanation

Desert mammals, such as Australian hopping mice and North American kangaroo rats, have many juxtamedullary nephrons with long loops of Henle that extend deep into the medulla, allowing them to produce highly concentrated urine. In contrast, aquatic mammals like beavers and muskrats have mostly cortical nephrons, resulting in a much lower ability to concentrate urine. Terrestrial mammals in moist conditions have intermediate loop lengths and urine concentrating ability.