Cells are the basic units of living things. They have very specialized functions in the organisms they are a part of. However, they are extremely small in size. Why is that? How can something so small contain so many organelles that are very specialized and yet be so efficient? The answer comes down to math. A smaller cell has a smaller surface area to volume ratio. This means that smaller cells are more efficient because waste, food, water or nutrients have a much smaller distance to travel into or out of the cell. If the cell were larger the particles entering or exiting the cell would have a greater distance to travel making the cell less efficient.