The voltage delivering 1 watt depends on how many amps are present. We use watts to measure power (P), and amps (I) times volts (E) equals watts.
The liver and the production of urea Urea is a nitrogen-containing substance which is produced in the liver, in order to deal with excess amino-acids in the body, which is a natural consequence of the fact that we almost always eat more protein than our body needs to assimilate. The process is called deamination.
The urea and water are released from the liver cells to the bloodstream and transported to the kidneys where the blood is filtered and the urea is passed out of the body in the urine.