Why am I human?

This is a question I often ask myself- it is one of the many questions that you can scientifically answer but you can never see an answer in your brain.

I often wonder what destined me to be human. I mean why aren't I a squirrel or maybe a plant or just a cell- why did I have to be a human being? Not that I don't like being a human, just that I am curious why my group of cells made me who I am without being anything else...