Ontario Grade 11 University Biology 2026 – 400 Free Practice Questions to Pass the Exam

The stomach plays a crucial role in the digestive system primarily through mechanical and chemical digestion of food. It serves as a muscular organ that contracts to mix and churn food, breaking it down into smaller pieces through mechanical means. This process is complemented by the secretion of gastric juices, which contain powerful acids and enzymes. These substances not only further break down food but also aid in killing potentially harmful bacteria.

The mechanical action of the stomach combined with the chemical processes allows it to convert food into a semi-liquid form called chyme. This preparation is essential for the effective absorption of nutrients, which occurs primarily in the small intestine after the initial digestion in the stomach. Thus, the stomach's dual role of physically and chemically processing food is foundational for the overall digestive process, making the selected response the most accurate regarding the stomach's function.