Final answer:
Gas exchange usually takes place in the pulmonary capillaries of the lungs, where oxygen diffuses into the blood and carbon dioxide diffuses out.
Step-by-step explanation:
Gas exchange in the body usually takes place in the pulmonary capillaries of the lungs. These capillaries are surrounded by thin-walled alveoli, which provide a large surface area for gas exchange to occur.
Oxygen from inhaled air diffuses into the blood across the capillaries, while carbon dioxide, a waste product, diffuses out of the blood and into the alveoli. This process of gas exchange is essential for supplying cells with oxygen and removing carbon dioxide waste.