Final answer:
Biliverdin is a green pigment produced as a breakdown product of hemoglobin. It is further reduced to bilirubin in the liver and contributes to the color of bile and feces.
Step-by-step explanation:
Biliverdin is a breakdown product of hemoglobin. When hemoglobin is broken down, the non-iron portion is converted into biliverdin, which is a green bile pigment. This process occurs when old or damaged red blood cells are removed from circulation by the spleen and then transported to the liver. In the liver, biliverdin is further reduced to bilirubin, which gives bile its green color and is eventually excreted in the feces after being transformed by intestinal bacteria into stercobilin, contributing to the characteristic brown color of stools.
The breakdown of hemoglobin can be observed visibly in various situations, such as the range of colors seen in a bruise (from biliverdin), the yellow tinge of jaundice (from bilirubin), and the typical brown color of feces (from stercobilins).