Final answer:
Urea is the urine constituent that is also found in the blood.
Step-by-step explanation:
The urine constituent that is also found in the blood is urea.
Urea is a non-toxic molecule made up of toxic ammonia and carbon dioxide. It is synthesized in the liver from ammonia released during the oxidation of amino acids. Urea is released into the blood and excreted in the urine at a concentration of 15-40 mg/100 ml of blood under normal conditions.