What is the primary function of the stomach?

The primary function of the stomach is to pummel food and produce pepsin, which is critical for digestion. The stomach has muscular walls that contract to mix and mechanically break down food into a semi-liquid form called chyme. This physical action, known as pummeling, is essential for increasing the surface area of the food, making it easier for digestive enzymes to work effectively.

In addition to mechanical digestion, the stomach lining produces pepsin, an enzyme that plays a vital role in the chemical digestion of proteins. Pepsin is activated in the acidic environment of the stomach, which is created by gastric juices containing hydrochloric acid. This acidic environment not only activates pepsin but also helps kill bacteria, providing a protective function.

The other options represent functions that occur in different parts of the digestive system. For example, bile production takes place in the liver and is stored in the gallbladder, while nutrient absorption primarily occurs in the small intestine, not the stomach. The storage of faeces is a function of the large intestine, further illustrating the distinct roles of these different organs in the digestive process.