Which of the following parts of the nephron is generally impermeable to water?

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

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

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

Components reabsorbed by the Proximal Convoluted Tubule $(PCT)$ - $P$
Components secreted by the Proximal Convoluted Tubule $(PCT)$ - $Q$
$I - K^{+}$,$II - \text{Ammonia}$,$III - HCO_{3}^{-}$,$IV - \text{Essential nutrients}$,$V - 70$ to $80\%$ $\text{electrolytes and water}$,$VI - H^{+}$
Select the correct option for $P$ and $Q$.
$P \quad\quad\quad Q$

In nephrons,there is complete absorption of