Question

____ aids dissolution because it disperses - or spreads out - the solute more evenly.
temperature
size of the solid
pressure
stirring or agitation

Explanation:

Stirring or agitation spreads out the solute in the solvent more evenly, increasing the contact between solute and solvent particles and thus aiding dissolution. Temperature affects solubility by changing the kinetic energy of particles, size of the solid affects dissolution rate through surface - area to volume ratio, and pressure mainly affects the solubility of gases.

Answer:

Stirring or agitation