Question

required information
what determines the direction of gas movement?
multiple choice
the temperature
the size of the gas molecule
the solubility of the gas in blood
the partial pressure differences
the ph

Explanation:

Gas movement occurs via diffusion. Diffusion is driven by concentration gradients. In the context of gases, partial pressure differences act as the concentration - like gradient. For example, in the lungs, oxygen moves from an area of higher partial pressure (in the alveoli) to an area of lower partial pressure (in the blood) because of this pressure difference. Temperature affects the kinetic energy of gas molecules but not the direction of movement. The size of the gas molecule affects the rate of diffusion (smaller molecules diffuse faster) but not the direction. Solubility of the gas in blood affects how much gas can be carried but not the direction of movement. pH is more related to the acid - base balance in the body and does not determine the direction of gas movement.

Answer:

The partial pressure differences.