Assetion : Secreting hypotonic urine is effective in reducing urinary loss of water .
Reason : Hypotonic urine is more concentrated and higher in osmotic pressure than the blood .

Options

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
B. If both the assertion and the reason are true and the reason is not a correct explanation of the assertion
C. If the assertion is true but the reason is false
D. If both the assertion and reason are false

Answer

D

Explanation

(d) When there is a threat of excessive water loss from the body of the animal,then the urine excreted needs to be hydpertonic and not hypotonic because excessive water loss from the body posses the threat of a rise in osmoconcentration of the blood. Since hyppertonic urine is more concentrated and higher osmomtic pressure than the blood , therefore it help in reducing the loss of water with urine . Mammals and birds can excrete hypertonic urine which is more concentrated than their blood. For this, an isotonic glomerular filtrate is first filtered into the Bowman's capsules of nephrons in kidneys . The tublues of nephorns then reabsorb a large volume of water frm the glomerular filatrate not accompanied by the rebsorption of proportionate amount of solutes. This leaves the urine more concentrated than the blood which is very effictive in reducing the urinary loss of water .