Which of the following criteria does not pertain to simple diffusion?

Diffusion rates are affected by the gradient of concentration, the permeability of the membrane separating them, temperature and pressure. Movement by diffusion is passive, and may be from one part of the cell to the other, or from cell to cell, or over short distances, say, from the intercellular spaces of the leaf to the outside. Diffusion is a slow process and is not dependent on a ‘living system’. Diffusion is very important to plants since it is the only means for gaseous movement within the plant body.