Every cell has chromosomes in its nucleus. In a human cell, there are 26 of them. AND ... lined up on every chromosome are thousands and thousands of GENES. Those carry the instructions for what kind of organ or bone or tissue or hair this cell will be used to build, how the structure will work, how tall you will be, what color your eyes will be, how deep your voice will be, and what illnesses you will have.
Every cell has the complete set of instructions in it. In the past several years, we have just started to be able to read them, and extraordinary progress has been made. There's an awful long way still left to go.
