Question

The kidneys in human beings are a part of the system for :
A. Nutrition
B. Respiration
C. Excretion
D. Transportation

Answer 1

Hint: Kidneys (two in number) are bean-shaped organs, on either side of a human’s spine, below the ribs and behind the stomach.

Complete Answer:
Kidneys' main role is to filter blood. They remove the wastes, control and maintain fluid balance of the body. The filtered blood goes back into the body. Waste gets turned into urine.

1. Nutrition - In humans is the procedure by which the food substances get transformed into body tissues and then provide energy for all the required activities.
2. Respiration - Respiration is the process of breathing in oxygen and breathing out carbon dioxide. In humans, it is carried out by the human respiratory system. Lungs are the chief organs for respiration.
3. Excretion - Excretion is the process of body’s toxic wastes’ removal. The different organs which remove wastes from the body are - kidneys and lungs. Lungs excrete the carbon dioxide and kidneys excrete the urea. So, the kidney is the main excretory organ in human beings.
4. Transportation - In humans, the transportation of - nutrients, hormones, oxygen, etc. to the tissues, carbon dioxide to the lungs and waste products to the kidneys - takes place in a significant way through the greatly developed Circulatory System. Whereas, in many other organisms, these materials are transported by the process of diffusion.

Therefore, the correct option is C) excretion.

Note: Under abnormal conditions, the kidneys lose its functionality to accomplish its routine tasks. In such situations, your doctor recommends you to go for a dialysis wherein the artificial kidneys perform this job for you.