Question

simple diffusion across membranes (b2.1.3)
describe factors that influence the rate of diffusion

Explanation:

The rate of simple diffusion across membranes is influenced by factors such as concentration gradient (higher gradient, faster diffusion), temperature (higher temperature, increased kinetic energy and faster diffusion), molecular size (smaller molecules diffuse faster), and membrane permeability (more permeable membranes allow faster diffusion).

Answer:

Concentration gradient, temperature, molecular size, membrane permeability.