Blood plasma is filtered from the blood capillaries into the nephron capsules, the walls of the capillaries and capsules act as a filter, retaining water and substances dissolved in it, with the exception of proteins. This is how primary urine is formed, which is similar in composition to plasma, but does not have blood cells and proteins.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.