Stale urine smells like ammonia because

The maximum quantity of water required per day by a human body is

The primary function of the kidney is ........ .

Which of the following statements is/are true?
$I.$ Urine is hypertonic while entering distal convoluted tubule.
$II.$ When the urine moves in the collecting tubule,it becomes hypertonic.
$III.$ Urine is isotonic in proximal convoluted tubule.
$IV.$ Urine becomes more and more hypotonic as it passes through the descending Henle's loop.

Why do we urinate more frequently during cold and humid weather?

Consider the following water conservation mechanisms:
$A.$ Nasal countercurrent mechanism
$B.$ Dependence on metabolic water
$C.$ Highly hypertonic urine
$D.$ Living more on protein-rich diet
The kangaroo rat living in the desert can survive without drinking water because of: