Which of the following processes involves diffusion?

The process that involves diffusion is "absorption of digested food into the villi." Diffusion is the movement of molecules or particles from an area of high concentration to an area of low concentration. This process occurs naturally and does not require energy input. In the case of absorption of digested food into the villi, nutrients such as glucose and amino acids are transported from the small intestine into the bloodstream. This process occurs through the walls of the villi, which are lined with a thin layer of epithelial cells. These cells are specialized for absorption and have microvilli on their surface that increase the surface area for nutrient absorption. As the digested food particles move from an area of high concentration (the small intestine) to an area of low concentration (the bloodstream), they diffuse across the cell membranes of the epithelial cells and into the bloodstream. This process allows the body to obtain the necessary nutrients from the food that has been consumed. While opening and closing of stomatal pores, turgidity of herbaceous plants, and absorption of water through the root hairs are all important biological processes, they do not involve diffusion. Therefore, the correct answer is "absorption of digested food into the villi."