Final answer:
Oxygen and carbon dioxide exchange in the capillaries surrounding the alveoli during external respiration through diffusion, where oxygen is taken into the blood and carbon dioxide is expelled from the body.
Step-by-step explanation:
Oxygen and carbon dioxide are exchanged in the capillaries that surround the alveoli in the lungs during a process known as external respiration. This exchange is vital for maintaining the body's respiration and involves two gases: oxygen (O2) and carbon dioxide (CO2). Oxygen is essential for cellular metabolism and is taken up by the blood, while carbon dioxide, a waste product of metabolism, is expelled from the body.
Detailed steps of this process include:
This transfer occurs because molecules tend to move from areas of higher concentration to areas of lower concentration, a process known as diffusion.