Final answer:
The lungs are the organ that is part of the respiratory system, where the exchange of oxygen and carbon dioxide occurs.
Step-by-step explanation:
The lungs are the organ that is part of the respiratory system. The respiratory system is composed of structures that are responsible for bringing air into the body, which includes the upper respiratory tract and the lower respiratory tract. Other parts of this system are the pharynx, larynx, trachea, and bronchi. The lungs are especially vital because they are where gas exchange between the blood and the atmosphere occurs. Inhaling brings air into the lungs, where oxygen is transferred to the bloodstream, and carbon dioxide is removed from the blood and exhaled.
While the heart is connected to the respiratory system through the circulatory system, it is not actually part of the respiratory system itself. Similarly, lymph nodes and ganglion are parts of the lymphatic and nervous systems respectively, not the respiratory system.