Which of the following pairs are part of the respiratory system?

• A. Aorta and left ventricle
• B. Superior vena cava and septum
• C. Trachea and alveoli
• D. Pulmonary vein and right atrium

Answer: (C)

Verified step by step guidance

1. Understand the respiratory system: The respiratory system is responsible for gas exchange, primarily oxygen intake and carbon dioxide removal. Key structures include the trachea, bronchi, lungs, and alveoli.
2. Analyze the first pair (Aorta and left ventricle): The aorta and left ventricle are part of the circulatory system, not the respiratory system. The left ventricle pumps oxygenated blood into the aorta, which distributes it to the body.
3. Analyze the second pair (Superior vena cava and septum): The superior vena cava and septum are also part of the circulatory system. The superior vena cava carries deoxygenated blood to the heart, and the septum separates the heart's chambers.
4. Analyze the third pair (Trachea and alveoli): The trachea (windpipe) is a tube that carries air to the lungs, and the alveoli are tiny air sacs in the lungs where gas exchange occurs. Both are essential components of the respiratory system.
5. Analyze the fourth pair (Pulmonary vein and right atrium): The pulmonary vein and right atrium are part of the circulatory system. The pulmonary vein carries oxygenated blood from the lungs to the heart, and the right atrium receives deoxygenated blood from the body.