Is the formation of only primary urine sufficient for the normal functioning of the body?

The formation of only primary urine for the body is not enough. In the primary urine, the nutrients necessary for the body remain. They are eliminated during the formation of secondary urine. Secondary urine per day is formed about 2 liters. Primary urine is produced in approximately 300 liters. Therefore, primary urine cannot be excreted from the body, since it contains the substances the body needs, and it is formed continuously in large quantities. Sometimes in the secondary urine there are substances necessary for the body. But this happens only with certain renal failure.