True or False: The wall of the stomach is impermeable to most substances.

The wall of the stomach is indeed impermeable to most substances, making the statement true. This impermeability is crucial for maintaining the integrity of the digestive process and protecting the body from harmful substances. The stomach's lining is designed to prevent the absorption of unwanted materials, allowing it primarily to break down food rather than absorb nutrients directly.

Additionally, the stomach's function is to digest food, which is aided by the secretion of gastric juices. These juices contain enzymes and acids that assist in breaking down food particles before they move into the intestines, where nutrient absorption occurs. As a result, while the stomach allows certain substances like water and possibly alcohol to pass through, it generally does not absorb nutrients or larger molecules, which happen further along in the digestive system, notably in the intestines.

Other choices suggest limited permeability or specific substances, which does not reflect the overall protective role of the stomach lining in maintaining a controlled environment conducive to digestion.