Which of the following organs is NOT found in the abdominal cavity?

The heart is the organ that is not found in the abdominal cavity. It is located in the thoracic cavity, which is the upper part of the trunk. The thoracic cavity houses the organs essential for respiration and circulation, including the heart and lungs.

In contrast, the stomach, liver, and kidneys are all located within the abdominal cavity. The abdominal cavity contains various vital organs involved in digestion, filtration, and excretion. Specifically, the stomach is crucial for digesting food, the liver plays a key role in metabolism and detoxification, and the kidneys are instrumental in filtering blood and regulating fluid balance. This anatomical distinction is essential for understanding the organization of the body's internal organs.