The main portion of all cells is filled with a fluid material. Just like a human
body, the interior of the cell contains food, waste material or even extra water.
On the outside of all cells is a protective covering called a membrane. It is just
tike the shell of an oyster. Sometimes cells divide in half, forming a new cell.
In other words, one cell splits in half and an exact duplicate forms. Now there
are two cells. When we are growing as a baby, cell division is responsible for
much of our growth.