What anatomical structure connects the stomach and the mouth?

The anatomical structure that connects the stomach and the mouth is the esophagus. The esophagus is a muscular tube that serves as a pathway for food and liquid to travel from the mouth to the stomach during the process of swallowing. It plays a crucial role in the digestive system, as it propels the ingested materials downward into the stomach through coordinated muscle contractions known as peristalsis.

The other options do not serve this function: the trachea is the airway that leads to the lungs, facilitating the passage of air rather than food; the spinal column is part of the skeletal system that protects the spinal cord and supports the body but does not have a digestive role; the hepatic duct is involved in transporting bile from the liver to the gallbladder and intestines, which is entirely separate from the pathway of food from the mouth to the stomach.