Q. Assertion Mammals, living in deserts contain more concentrated urine.
Reason They contain very long loop of Henle in their nephrons.

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Solution:

Functional unit of kidney is known as nephron. Later contains a tubular region between proximal and distal convoluted tubule, the loop of Henle. The length of loop of Henle is proportional to the concentration of urine. The mammals (chordates) living in desert contain longer loop of Henle in their nephrons. Due to this, these animals contain more concentrated urine.