Final answer:
The presence of urobilin in the feces of a healthy adult is true, as it is a product of the breakdown of bilirubin in the intestines by bacteria, which is a normal part of the waste elimination process.
Step-by-step explanation:
The statement that in a healthy adult, urobilin is positive in feces is True. The non-iron portion of heme is transformed into the waste products biliverdin, and then bilirubin, which is a yellow pigment. Bilirubin is brought to the liver, and it is used in the production of bile for the digestion of fats. In the large intestine, bilirubin is broken down by bacteria into urobilinogen, which is further converted into stercobilin, giving feces its brown color. Urobilinogen can also be converted into urobilin, which may be excreted in urine. Changes in this process, such as those brought on by broad-spectrum antibiotics which can eliminate the bacteria responsible for this conversion, may affect the color of feces.
Bilirubin is the main bile pigment and the green color of bile is due to this substance. When this bilirubin does not enter the intestine, due to specific disease states, feces may appear white ('acholic') and contain a high fat content.