sentence2_structure: Diffusion<>is<>the process in which a substance naturally moves from an area of higher to lower concentration$$$a substance<>naturally moves<>from an area of higher<>to lower concentration<>the process
sentence1: Diffusion is the chemical process when molecules from a material move from an area of high concentration (where there are lots of molecules) to an area of low concentration (where there are fewer molecules).
sentence2: Diffusion is the process in which a substance naturally moves from an area of higher to lower concentration.
question: What is the process in which a substance naturally moves from an area of higher to lower concentration called?