Main components of urine are salt , water and waste products.
The major waste product from cells in the body is ammonia, and the
major waste product from blood is a broken form of heme called
bilirubin.
In the liver, each of these is converted into a less hazardous
form: ammonia is converted to urea, and bilirubin is degraded to
urobilins. Salt, water, and urea are all colorless, but urobilins
(which come from degraded pigments) are yellow. So, if you drink a
lot, your urine will be more dilute and clearer, and if you get
dehydrated, your urine will contain less water and be darker
yellow.
froom google
