Question

diffusion works best with...
particles trapped in limited space.
particles that are stationary.
solid materials.
moving particles suspended freely in a solution.

Explanation:

Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration. For diffusion to occur, particles need to be able to move. Stationary particles (option 2) cannot diffuse. Particles trapped in a limited space (option 1) have restricted movement, which is not ideal for diffusion. Solid materials (option 3) have particles that are closely packed and have limited movement compared to particles in a solution. Moving particles suspended freely in a solution (option 4) can move and spread out, which is what diffusion requires.

Answer:

moving particles suspended freely in a solution.