Question

The concentration gradient of the renal interstitium increases from the cortex to the tip of the medulla, this causes the urine to:

		Become more concentrated
		Become more dilute
		To leak through the basement membrane
		To help retain nutrients in the blood

Answer 1

Solution:

∆ urine is become more concentrated

Here concentration gradient means in renal medulla. As the blood circulation slow in blood cappillaries, the absorbed contents will reabsorbed into medulla, or water re absorption happening. Increased amount if sodium and urea cause urine become more concentrated.

∆To help retain nutrients in blood

Concentration gradient is based on sodium and urea, not about nutrients. Here nutrients are not affected. Those nutrients are stable in blood only.

Other 2 options are incorrect, because

×Become more dilute: concentration gradient makes urine concentrated, not diluted.

×To leak through basement membrane: for a normal kidney function, there should not be such abnormal leaking. Concentration gradient depends on reabsorotion of water only, not leaking of urine.