Which one of the following is likely to accumulate in a dangerous proportion in the blood of a person whose kidney is not working properly?

Struvite stones are derived from . . . . . . .

Uremia is a disease related to the

Acute renal failure $(ARF)$ is characterised by . . . . . . .
$i$. Irreversible increase in glomerular filtration rate.
$ii$. Frequent elimination of large quantities of urine.
$iii$. Sudden worsening of renal function.
$iv$. Elevated serum creatinine levels.
Select the correct option given below.

Blood is drained from a convenient $P$ of a patient and is pumped into a dialyzing unit after adding $Q$. After purification,$R$ is added to the blood,and it is returned to the body through $S$.
$\quad \quad P\quad \quad Q\quad \quad R\quad \quad S$

Inflammation of glomeruli of kidney is known as: