Answer:
Cells are small to have a larger surface area to volume ratio
Explanation:
Since there is always things moving across the phospholipid bilayer of the cell, there needs to be a large surface area compared to volume. A good analogy that I use is elephants ears. They are huge but super thin to keep a large surface area to volume ratio. This lets heat diffuse from the elephant. Its the same thing with cell, maximizing the efficiency of the phospholipid bilayer.
