Describe 3 ways in which materials are transported across the cell membrane

(When molecules move in this way, they are said to move down their concentration gradient.) Three common types of passive transport include simple diffusion, osmosis, and facilitated diffusion. Simple Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.