Which one of the following animals has a longer loop of Henle?

Assertion : In the descending limb of the loop of Henle,the urine is hypertonic,whereas in the ascending limb of the loop of Henle,the urine is hypotonic.
Reason : The descending limb is impermeable to sodium,while the ascending limb is impermeable to water.

In human kidneys,which substances are mainly responsible for creating the osmolarity gradient of the medullary interstitial fluid?

Mention the substances that exit from the tubules in order to maintain a concentration gradient in the medullary interstitium.

In vertebrates,the ability to produce concentrated urine is generally associated with the ............ .

Which of the following statements is correct?