Answer:
The label that shows the movement of oxygen in the diagram of gas exchange in the lungs is "2: Diffusion of Oxygen into the Bloodstream".
In the lungs, oxygen moves from the air in the alveoli (air sacs) into the bloodstream. This process is known as diffusion. Diffusion is the movement of molecules from an area of high concentration to an area of low concentration. In this case, oxygen molecules move from an area of high concentration in the alveoli to an area of lower concentration in the bloodstream.
During inhalation, fresh air containing oxygen enters the alveoli. Oxygen molecules then pass through the thin walls of the alveoli and into the surrounding capillaries. Capillaries are tiny blood vessels that surround the alveoli. The walls of the capillaries are also very thin, which allows for the exchange of gases.
The oxygen molecules diffuse through the walls of the alveoli and capillaries and into the red blood cells. Inside the red blood cells, oxygen binds to a protein called hemoglobin. Hemoglobin carries oxygen to the body's cells, where it is used for various metabolic processes.
So, in summary, label 2 in the diagram represents the movement of oxygen as it diffuses from the alveoli into the bloodstream, where it binds to hemoglobin and is transported to the body's cells.
Step-by-step explanation: