What does the movement of substances in chromatography depend on?

The correct answer focuses on the rate at which different components travel during the chromatography process. In chromatography, substances are separated based on their differing affinities for the mobile phase (the solvent) and the stationary phase (the material on which the substances are spread, such as paper or silica gel).

Each component of a mixture interacts differently with these phases; some may adhere more to the stationary phase and move more slowly, while others may dissolve better in the mobile phase and travel faster. This differential movement allows for the separation of the components, making it possible to identify or quantify the substances present in the mixture. Thus, the separation relies significantly on the rates at which the different components can move through the system.

The other options do not capture the essential principle of chromatography. Temperature may influence the mobility of substances to some extent, but it is not the primary factor. The color of the substances relates to their visibility and identification, not to the mechanism of separation. The size of the paper used could affect how much sample can be analyzed, but it is not a fundamental aspect of how substances are separated in chromatography.