Which of the following is mismatched?

$I.$ Reabsorption of water occurs passively in the initial segment of nephron.
$II.$ Nitrogenous wastes are absorbed by active transport.
$III.$ Conditional reabsorption of $Na^{+}$ and water takes place in $DCT$.
$IV.$ $DCT$ reabsorbs glucose.
$V.$ $DCT$ is capable of selective secretion of $H^{+}$,$K^{+}$ and $NH_{3}$ to maintain $pH$ and $Na^{+}-K^{+}$ balance in blood.
$VI.$ Substances like glucose,amino acids,$Na^{+}$,etc.,in the filtrate are reabsorbed actively.
Choose the option with incorrect statements.

The amount of the original filtrate volume which is reabsorbed by the time the tubular fluid enters the Henle's loop is approximately (in $\%$)

The brush border is a characteristic of which of the following?

Reabsorption of glucose from the glomerular filtrate in the kidney tubule is carried out by

In which part of the nephron are the majority of electrolytes and water ($70$ to $80\%$) reabsorbed from the glomerular filtrate?