8 of 108 of 10 items 06:53 question i. moves molecules from high to low concentration ii. moves molecules with the concentration gradient iii. does not require energy iv. requires the use of a membrane protein v. used to move small and/or nonpolar molecules vi. used to move large and/or polar molecules cell membranes are selectively permeable, regulating which substances can pass through, as well as how much of each substance can enter or exit at a given time. in cells, some molecules can move down their concentration gradients by crossing the phospholipid portion of the membrane directly, while others must pass through membrane proteins. which of these statements applies only to facilitated diffusion and not diffusion