Separate body structures that perform a specific function; lungs are an example.

Separate body structures that perform a specific function; lungs are an example.

• A. Cells
• B. Tissues
• C. Organs
• D. System

Answer: (C)

Organ structures are made up of different tissues that come together to perform a specific function. The lungs fit this description because they are composed of multiple tissue types—such as epithelial lining for air passages, elastic connective tissue, smooth muscle in the airway walls, and specialized tissue for blood vessels and gas exchange—and together they carry out the essential function of exchanging oxygen and carbon dioxide between the air and the bloodstream. This isn’t a cell or a single tissue, which are smaller units of organization. It isn’t a system, either—the system is a group of organs working together, like the respiratory system. So the lungs are an organ, the body’s structure designed to perform the specific task of respiration.

Organ structures are made up of different tissues that come together to perform a specific function. The lungs fit this description because they are composed of multiple tissue types—such as epithelial lining for air passages, elastic connective tissue, smooth muscle in the airway walls, and specialized tissue for blood vessels and gas exchange—and together they carry out the essential function of exchanging oxygen and carbon dioxide between the air and the bloodstream.

This isn’t a cell or a single tissue, which are smaller units of organization. It isn’t a system, either—the system is a group of organs working together, like the respiratory system. So the lungs are an organ, the body’s structure designed to perform the specific task of respiration.