-Priyanti, Subject Matter Expert at Edumarz
Solution: c) Excretion
The main function of the kidneys includes removal of wastes, maintaining water content of the body and regulating osmotic balance. From an evolutionary standpoint, the kidneys have been developed in order to enable humans to pursue a terrestrial lifestyle and conserve water and salts. So they have to excrete wastes in a concentrated manner and maintain the volume, integrity and osmotic pressure of the tissue fluids in the process. Salts of minerals such as sodium, potassium, calcium, phosphorus and bicarbonates are maintained at their proper levels as a consequence of the above process. Thus, the kidneys are the major organs participating in the excretory system of the body.
Structure of a kidney