Exchange of gases takes place in which of following organs?

Correct Answer: B. Lungs

Gas exchange is the transport of oxygen from the lungs to the bloodstream and the expulsion of carbon dioxide from the bloodstream to the lungs. It transpires in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.

• Option A: The renal system consists of the kidney, ureters, and urethra. The overall function of the system filters approximately 200 liters of fluid a day from renal blood flow which allows for toxins, metabolic waste products, and excess ions to be excreted while keeping essential substances in the blood. The kidney regulates plasma osmolarity by modulating the amount of water, solutes, and electrolytes in the blood. It ensures long-term acid-base balance and also produces erythropoietin which stimulates the production of red blood cells.
• Option C: The liver is a critical organ in the human body that is responsible for an array of functions that help support metabolism, immunity, digestion, detoxification, vitamin storage among other functions. It comprises around 2% of an adult’s body weight. The liver is a unique organ due to its dual blood supply from the portal vein (approximately 75%) and the hepatic artery (approximately 25%).
• Option D: The heart is a muscular organ situated in the center of the chest behind the sternum. It consists of four chambers: the two upper chambers are called the right and left atria, and the two lower chambers are called the right and left ventricles. The right atrium and ventricle together are often called the right heart, and the left atrium and left ventricle together functionally form the left heart.