Function of kidney is:

Question

Function of kidney is:

1. A. respiration
2. B. nutrition
3. C. transportation
4. D. excretion (Correct answer)

Correct Answer

Option D — excretion

Detailed Solution & Explanation

The correct answer is excretion.

Key Points

• The kidneys carry out excretion — filtering nitrogenous waste, chiefly urea, from the blood and removing it as urine.
• Respiration is performed by the lungs, nutrition by the digestive system, and transportation by the blood and circulatory system.

Additional Information

• The functional unit of the kidney is the nephron; each kidney contains roughly one million of them.
• Beyond excretion, the kidneys regulate water and electrolyte balance, blood pressure (through renin) and red blood cell production (through erythropoietin).
• Urine passes kidney → ureter → urinary bladder → urethra. When the kidneys fail, dialysis performs the filtration artificially.