Ans. 1. Ultrafiltration – It is a passive process that takes place from the glomerulus into Bowman's capsule. The different arteriole is narrower as compared to the afferent arteriole and a high pressure develops in the glomerulus which enables a large amount of filtrate into the  Bowman's capsule.  Glomerular Filtration at Rate – It is the filtered blood entering into the Bowman's capsule. In a  normal adult, it is 120 ml per minute and about 180 litres per day An adult man normally passes  1 to 1.8 litres of urine in 24 hours.  2. Reabsorption – It is the process due to glomerular filtrate being returned into the bloodstream. 3. Tubular Secretion – It is the supporting mechanism for filtration and reabsorption.