Which of the following is typically found in fecal waste?

• A. Oxygen and carbon dioxide
• B. Bile pigment, mucus, undigested fats, cellulose, protein, desquamated cells, electrolytes, water, undigested foods
• C. Bile acids only
• D. Saliva

Answer: (B)

Fecal waste is a mix of water and a variety of nondigested or shed materials from the digestive tract. A typical stool contains bile pigment (which gives it brown color), mucus to help lubrication, undigested fats and other undigested foods, cellulose and other plant fiber, residual protein, desquamated cells from the lining, electrolytes, and water, along with bacteria and other microbial byproducts. Oxygen isn’t a meaningful part of solid stool because the gut environment is largely anaerobic, and saliva is not a component of waste once it’s processed through the digestive system. Bile acids exist in the gut, but feces include many other components beyond them. So the description listing bile pigment, mucus, undigested fats, cellulose, protein, desquamated cells, electrolytes, water, and undigested foods best represents what’s typically found in fecal waste.