The ratio of surface area (SA) : volume (V) is important because it indicates whether the supply can meet the demand. A low SA : V ratio indicates that the cell will be unable to supply nutrients and remove wastes fast enough to meet its needs. As a cell increases in length its surface area does not increase to the same extent as its volume. Larger organisms tend to have lower surface area to volume ratios. This makes it difficult or impossible for large cells to absorb nutrients and remove wastes quickly enough to stay alive. In order to have a high surface area to volume ratio cells must be small.