How surface area affects the rate of a reaction.

The smaller the surface area, the faster the rate of reaction will be. Think of ice. A full sized ice cube will take longer to melt than crushed ice. Crushed ice will melt much quicker because there is more surface area exposed. So if the surface area can be increased, so will the rate of reaction.

Hope this helps! :)

Here is a hint, mitosis is the division of cells.