CBSE Class 10 Answered

This is because after glomerular filtration, selective tubular reabsorption takes place due to which as much as 99 per cent of the material in the filtrate is reabsorbed, preventing the loss of water, nutrients, and ions from the body. As a consequence of tubular reabsorption urine contains mostly waste materials  and excess water. Certain chemicals in the blood that are not removed by filtration from the glomerular capillaries are removed by a third process of urine formation called tubular secretion.Both these processes bring down the huge volume of glomerular filtrate to about 1.5 litre of urine produced.