A concentration gradient refers to the gradual change in the concentration of solutes in a solution between two regions. This difference in concentration can drive the movement of particles, such as molecules or ions, from an area of higher concentration to an area of lower concentration, a process known as diffusion. Concentration gradients are essential for various biological processes, including cellular respiration and photosynthesis. In living organisms, concentration gradients play a crucial role in maintaining homeostasis. For example, in cells, nutrients and waste products move across cell membranes along these gradients, ensuring that essential substances enter the cell while waste is expelled. This movement is vital for the proper functioning of cells and overall health.