As the cell size increases what will happen ?
As cell size increases, the surface area increases and the surface-area-to-volume ratio decreases.
When the cell expand or the size of cell increases the surface area of cell is also increases because surface area of cell is directly proportional to cell size.
The volume of any thing remains same no matter how much changes made in surface area. So on increasing surface are and volume remain same, the surface-area-to-volume ratio will decrease.