Which of the following statements is correct about diffusion?
A) It requires an expenditure of energy by the cell.
B) It is a passive process in which molecules move from a region of higher concentration to a region of lower concentration.
C) It is an active process in which molecules move from a region of lower concentration to one of higher concentration.
D) It may require a transport protein.
E) It involves movement of molecules down a concentration gradient and may require a transport protein
Answer: E