The portion of nephron which is relatively impermeable to water is

$A :$ Kidneys are retroperitoneal in position.

$R :$ Kidneys are covered with peritoneum only on ventral surface.

Inner to hilum of the kidney, there is a broad funnel-shaped space called

Choose incorrect sentence.

$(I)$ Malpighian corpuscles, $PCT$ and $DCT$ the nephron are situated in medulla of the kidney

$(II)$ The loop of henle dips into medulla.

$(III)$ In juxta medullary nephrons, the loop of henle is too short and extends very little into the medulla.

$(IV)$ Vasa recta is absent or highly reduced in cortical nephrons.

Identify the wrong statements about human excretory system and choose the option accordingly

$I.$ Kidneys are reddish brown and bean-shaped structure

$II.$ Kidneys are situated between the last thoracic and third lumber vertebra

$III.$ Each kidney of an adult human measures $10-12\, cm$ in length, $5-7\, cm$ in width, $2-3 \,cm$ thickness, and average weight $120-170$ $gram$

Part of the kidney through which the ureter, blood vessels and nerves enters into it is