CBSE Class 10 Answered

Alveoli are sac like structures present in the lungs whereas nephrons are the basic filtration units of the kidneys.

1) Both alveoli and nephrons are designed to provide a large surface area.

2) They are both richly supplied with blood through a dense networks of blood capillaries. 

3) Both alveoli and nephrons help in the process of excretion. Alveoli excrete carbon dioxide during exhalation. Nephrons excrete excess water, salts, ions, urea, and other nitrogenous wastes.

4)  In the alveoli, oxygen from air diffuses into the blood and carbon dioxide from blood diffuses into alveoli. In the nephrons, pressure filtration of glomerular filtrate occurs into the Bowman’s capsule.This is followed by selective reabsorption of useful materials and secretion of the waste substances in to the urine.