Questions: Diffusion of gas The direction of the diffusion of gas is determined by Multiple Choice temperature. movement of blood. levels of cholesterol. partial pressure differences. pH .

The answer is the fourth one: partial pressure differences.

Explanation for each option:

1. Temperature: While temperature can affect the rate of diffusion (higher temperatures generally increase the rate), it does not determine the direction of diffusion. The direction is determined by concentration or pressure gradients.

2. Movement of blood: This is not directly related to the direction of gas diffusion. Blood movement can affect the transport of gases once they have diffused, but it does not determine the direction of diffusion itself.

3. Levels of cholesterol: Cholesterol levels are not related to the diffusion of gases. Cholesterol is a component of cell membranes and does not influence the direction of gas diffusion.

4. Partial pressure differences: This is the correct answer. The direction of gas diffusion is determined by differences in partial pressure. Gases will diffuse from an area of higher partial pressure to an area of lower partial pressure until equilibrium is reached.

5. pH: While pH can affect the solubility and reactivity of gases in solution, it does not determine the direction of gas diffusion. The direction is determined by partial pressure differences.

In summary, the direction of gas diffusion is determined by partial pressure differences, as gases move from areas of higher to lower partial pressure.