Which of the following body parts is not included in the respiratory tract?

The stomach is the correct answer because it is not part of the respiratory tract. The respiratory tract is primarily responsible for the process of breathing and includes structures that facilitate the exchange of gases, namely oxygen and carbon dioxide.

The respiratory tract begins with the nose and moves through the throat, extending downward to the trachea and into the lungs. Each of these components plays a critical role in inhaling air, filtering and warming it, and allowing for gas exchange within the lungs. In contrast, the stomach is a component of the digestive system, where food is broken down and processed, and it does not participate in the respiratory functions of inhalation and gas exchange.

Understanding the distinction between the systems is key in anatomy and physiology, as each body system has specialized components that serve their specific purposes.