Answer:
The idea of concentrations and gradients within them is important when understanding the movement of substances across cell membranes. The more particles there are in a certain volume, the more concentrated those particles are. A solution with a low solute concentration has a high water concentration, and a high water potential.
The inner layer of the stomach is full of wrinkles known as rugae (or gastric folds). Rugae both allow the stomach to stretch in order to accommodate large meals and help to grip and move food during digestion.
