Desert animals need to conserve water. Kidneys regulate the concentration of salt and water in blood through the formation and excretion of urine. A kidney is composed of approx. 1 million units called nephrons. The kidneys of desert animals have modofied nephrons which help them survive long period without water. Which one of these options would be the expected modification?
1. A very short collecting duct
2. A very long loop of Henle
3. A very short distal tubule
4. A very large Bowman's capsule
Option 2 is right.
.Desert animals have very long loop of Henle, so that they can produce extremely concentrated urine so as to lose as little water as possible.