What is the driving force that causes inert gas to dissolve into the body’s tissues?

The correct choice identifies the pressure gradient between the partial pressure of inert gas in the alveoli and the surrounding tissues as the primary driving force for the dissolution of inert gases into body tissues.

Inert gases, such as nitrogen, are present in the air we breathe and can dissolve into the body's tissues depending on their partial pressure. The principle governing this process is Fick's law of diffusion, which states that gases will naturally move from areas of higher concentration (or partial pressure) to areas of lower concentration until equilibrium is reached. When a diver breathes air at increased pressure, the partial pressures of its components increase, leading to a higher concentration of inert gases in the alveoli. This higher concentration creates a gradient that promotes the diffusion of those gases from the alveoli into the surrounding tissues where the partial pressure is lower.

The other options do not accurately describe the mechanism behind gas dissolution in body tissues. The gradient between the right and left ventricles of the heart is unrelated to gas exchange or tissue saturation. Similarly, the difference in temperature between surface water and the thermocline impacts aquatic life and buoyancy but does not directly influence inert gas dissolution. Finally, the pressure difference between the alveoli and the lungs does not facilitate the movement of gases into