Urine leaves the body through a sphincter in the process of urination.
Fluids in the urine eliminate metabolic waste products.
Metabolic waste products can leave the body through a sphincter.
Metabolic waste products can leave the body through
Options:
  * burning coal
  * animal transport
  * Dehydration
  * radiative transfer
  * osmosis
  * convection
  * fossil fuels
  * a sphincter