Water, urea, glucose, salts, amino acids, and some
vitamins pass out of the blood, through membranes, and into the kidneys. plasma
proteins, cells, and platelets do not. suggest an explanation for this observation

Answer and Explanation:

Ultrafiltration occurs in the capsular space of the glomerulus. The high blood pressure causes the glucose, urea, salts, amino acids and some vitamins to pass through because of their small size forming a filtrate. Glucose, urea, salts, amino acids and some vitamins are reabsorbed in specific parts of the renal corpuscle. Blood cells and blood protein molecules because of their large size remain inside the glomerular capillaries and are taken back to the system by efferent arteriole. Large and polar molecules e.g. blood components and plasma proteins cannot pass through the fenestrated capillaries.  

allowed for the prediction of the properties of missing elements.