Question

The entire volume of blood is filtered by kidneys………. times a day.
A. Once
B. $5$
C. $100$
D. $60$

Answer 1

Hint: Approximately $20\% $ of amount of blood pumped by the heart is filtered by your kidneys per minute under resting conditions. In humans kidneys produce about $125$ mL/min filtrate in men that ranges from $90$ to $140$ mL/minute and $150$ mL/min filtrate in women that ranges from $80$ to $125$ mL/minute.

Complete answer:
The main function of the kidney is to make urine by removing waste products and excess fluid from the body.
Human kidneys are made up of about a million of filtering units called nephrons. Nephron is the basic unit of the kidney. Each nephron has a filter called a glomerulus and a tubule. Whole blood enters glomerulus, where filtration of blood takes place, and the tubule returns absorbed substances from the blood that are needed by the body and removes waste.
Filtration is the complex process where extensive movement of water and solutes occur from plasma to the renal tubule.
Around $20\% $ of the plasma volume that passes by the way of the glomerulus at any given time is filtered.
So it is evident from the fact that about $180$ litres of fluid are filtered by the human kidneys per day. Thus, kidneys filter the whole plasma volume i.e., about 3 litres,$60$ times a day.
Hence, the correct option is (d)$60$.

Note:
In average adult human body urine production is about $1 - 2$ litres (L) per day. It totally depends on state of hydration, activity level, environmental factors, weight, and the individual's health.
$1200$ mL per minute (i.e., about one-fourth of the entire cardiac output) is the rate at which the blood passes through the kidneys.