Which of the following disorders is associated with the digestive system?

Peptic ulcers are indeed associated with the digestive system. They are sores that develop on the lining of the stomach, small intestine, or esophagus, primarily due to the detrimental effects of stomach acids. This condition often arises from factors such as infection with Helicobacter pylori bacteria, prolonged use of nonsteroidal anti-inflammatory drugs (NSAIDs), or excess gastric acid secretion. The presence of peptic ulcers can lead to symptoms such as stomach pain, bloating, and indigestion, ultimately impacting the digestive process.

In contrast, the other disorders listed—emphysema, pneumonia, and acute bronchitis—primarily affect the respiratory system. Emphysema involves the destruction of the air sacs in the lungs, pneumonia refers to inflammation of the lung tissue often due to infection, and acute bronchitis is the inflammation of the bronchial tubes. Each of these conditions relates to breathing and lung function rather than to digestive health.