Which of the following features activates the $JG$ cells?
$I.$ Fall in $GBP$
$II.$ Fall in $GBF$
$III.$ Fall in $GFR$
Choose the correct option.

Angiotensinogen protein is produced and secreted by . . . . . . .

Select the correct option with respect to the following statements:
$(a)$ Angiotensin $II$ constricts arterioles in the kidney to reduce blood flow and decreases blood pressure when blood flow to the afferent arteriole decreases.
$(b)$ Angiotensin $II$ stimulates the adrenal cortex to release aldosterone for more absorption of $Na^+$ and $Cl^-$ ions in the $DCT$.
$(c)$ Blood osmolarity varies with the secretion of aldosterone and $ANP$.

The urine of a man is very dilute,the quantity of urine is excessive,dehydration has started in his body,and he is very thirsty. This condition is caused by:

If there is a deficiency of $ADH$ (antidiuretic hormone),what would be its effect?

Juxtaglomerular cells of renal cortex synthesize an enzyme called