Why Do Mammals Adapted to Dry Climates Tend to Have

Why do mammals adapted to dry climates tend to have considerably more long- looped nephrons than those adapted to wet climates?

A) So that a higher concentration of salt can be produced in the interstitial fluid of the kidney medulla, causing more water to be reabsorbed into the capillaries
B) So that the excess urea they produce as a result of dehydration can be properly filtered by the nephrons and excreted
C) So that their blood pressure does not drop to dangerously low levels during periods of drought
D) So that a lower concentration of salt can be produced in the interstitial fluid of the kidney medulla, causing less water to be reabsorbed into the capillaries
E) So that the wastes can be excreted as uric acid instead of urine