without the expenditure of energy, the net movement of matter in a physiological gradient will always be…

without the expenditure of energy, the net movement of matter in a physiological gradient will always be from a region of ______ concentration to a region of ______ concentration.\no lower; higher\no higher; lower
Answer
Brief Explanations:
This is based on the principle of diffusion. Diffusion is the passive movement of substances from an area of higher concentration to an area of lower concentration without the use of energy.
Answer:
B. higher; lower