Question

What is it advantage for cells to be small

Answer 1

Cells have such a small size for their own benefit. First they are small in size to allow nutrients and other materials to diffuse through the cell membrane, they keep a small ratio of surface area to volume. Also the size of cells makes them easier to reproduce and replace, as this is a constant process.

Answer 2

Cells are so little, so they can maximize their ratio of surface area to volume. Smaller cells have a higher ratio which allow more molecules and ions move across the cell membrane per unit of cytoplasmic volume. Cells are so small because they need to be able to get the nutrients in and the waste out quickly.