Final answer:
The tongue's role in chewing and swallowing involves physically manipulating food and forming it into a bolus before moving it to the pharynx for swallowing, where peristalsis then moves it into the stomach.
Step-by-step explanation:
The role of the tongue in chewing and swallowing is primarily physical, not chemical. During the chewing process, the tongue and teeth work together to mechanically break down the food. Saliva from the salivary glands moistens the food and begins chemical digestion with enzymes such as salivary amylase and lipase.
The tongue then helps to form the chewed and moistened food into a small mass called a bolus. Once the bolus is ready, the tongue moves it to the back of the mouth, into the pharynx (not the larynx). From there, a series of involuntary muscle contractions known as peristalsis conveys the food through the esophagus towards the stomach. It is important to note that the tongue does not secrete saliva, nor does it move food into the larynx, which is part of the respiratory system and closes during swallowing to prevent food from entering the airways. The correct role of the tongue, therefore, aligns with option (A).