Final answer:
A bolus is a small mass of food that is chewed and combined with saliva, making it suitable to be swallowed. It then travels through the esophagus to the stomach, where it is processed into chyme. Bile, on the other hand, is involved in fat digestion within the small intestine.
Step-by-step explanation:
A bolus is C. A small mass of food, formed by chewing, that is swallowed. When we chew our food, it mixes with saliva, which contains enzymes that begin the process of digestion. This chewed and saliva-moistened food is then formed into a bolus that makes it easier to swallow. The bolus passes from the mouth into the pharynx, continues into the esophagus, and is pushed down by peristaltic movements towards the stomach for further digestion. Once in the stomach, it is mixed with digestive juices becoming a thick semi-liquid mixture called chyme.
It's important to note that bile is a digestive juice produced by the liver, crucial for emulsifying fats, and it mixes with chyme in the small intestine, not the stomach. Also, the waste product material that is expelled through the anus is not a bolus but rather feces, resulting from the elimination process of undigested food content and waste products.