Through the process of simple diffusion, materials move across a cell membrane from an area of higher concentration to an area of lower concentration.
Answer: Option C
Explanation:
Simple diffusion is the process of spontaneous transfer of molecules or materials from one place to other through a thin semi-permeable or permeable membrane. In any organism, cell membranes acts as semi-permeable membrane which will allow the required and necessary materials to pass through it.
And it fluid mechanics, it is known that fluids or materials in fluids usually flow spontaneously without any explicit external force from higher concentration to lower concentration. The term “explicit” is mentioned here because, the external force is there but it is completely visible.
In fluid mechanics, the unbalance in the concentrations will create unequal drag forces or flow force and that will act as external force. Thus, for occurring simple diffusion via a cell membrane, the materials in the fluid tend to flow from higher concentration to lower concentration.