______________ is the exchange of oxygen and carbon dioxide across the alveolar membrane.

Question

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Diffusion is the passive movement of a substance from high concentration to low concentration. During inhalation, oxygen in the alveoli has to make its way into the blood, and this occurs via diffusion. A high oxygen concentration in the alveoli drives the movement of oxygen into the pulmonary capillaries where oxygen content is low. Conversely, carbon dioxide is also exchanged this way, but is unloaded, or moved from the blood to the alveoli for exhalation.
You may use the diagram below as a visual reference for the structures of the respiratory system.
 11ec0fb7_27f7_8f1f_95f0_d90c95c39c34_NR0002_00 Osmosis is a type of diffusion, however it involves the movement of water across a membrane. This happens when particles or substances are not able to pass through a membrane. This is not what happens at the alveoli, as the movement of gas molecules is necessary.
Exocytosis is a type of vesicular transport which involves the release of a substance from inside a cell to outside a cell as the vesicle is dissolved.
Active transport is a type of membrane transport that requires ATP, usually because a substance needs to move against its concentration gradient, rather than along with the gradient.

______________ Is the Exchange of Oxygen and Carbon Dioxide Across