Explain why cells are so small, considering the relationship between surface area and volume for objects of different sizes but similar shapes

Explain like a 6th grader would

Well im a 7th grader so ok it can be true that cells were just small they did not know how to grow bigger so they just stay still traveling around living organisims after a while a cell meets another cell and the and join together to make bigger cells all to make tissues and tissiues made organs organs make systems and the system to make the organism. note i go to a jamaican school so we kinda learn more quicker than u guys.