The surface area and the volume of the cell plays an important role in uptake or exchange of substances. Surface area refers to the area of the cell exposed to the external environment and the volume refers to the amount of the space within the cell. As the size of the cell increases, the surface area to volume ratio decreases making the process of nutrient intake, exchange and removing unwanted material difficult. It is because, cells depend on diffusion for the process and larger cells show less efficiency in diffusion.