The collecting tubules lead into ducts called

Select the $CORRECT$ statements:
$i$. Tubular secretion involves secretion of $H^{+}$ ions in $PCT$.
$ii$. Augmentation involves secretion of $H^{+}$ ions in $DCT$ and $CT$.
$iii$. Augmentation plays an important role in regulation of $pH$ of blood.
$iv$. Glomerular filtrate as well as urine are acidic.

Glucose and amino acids in the filtrate are reabsorbed by tubular epithelial cells through

Select the incorrect option for the $Vasa$ $recta$.

The mechanism of uric acid excretion in a nephron is:

The brush border is a characteristic of ..........