Answer – Simple diffusion is a transport process in which the direction of movement of substances is determined by their concentration gradients i.e from regions of higher concentrations to those of lower concentrations.
Explanation:
When two (or more) substances are present in an area, a concentration gradient is set up when the particles of one substance are unevenly distributed, resulting in regions where they are present in higher concentration compared to others.
When this happens in a fluid, there is a tendency of the particles to move from regions of higher concentration to those where they are less abundantly present. This is called simple diffusion. The movement of these particles is driven by the difference in concentration, and does not require any external assistance.
Simple diffusion can also take place across a selectively permeable membrane. As it does not require energy or facilitation by specialized molecules, in biology, simple diffusion is categorized as a method of passive transport.
