Extra Parts

I remember growing up, and hanging out in my Grandfather's garage, and being amazed at his ability to take an automobile apart, put it back together, and it ran like a top (most of the time). But there were always extra parts left over, especially nuts and bolts. I used to think, "Don't those have to go back into the vehicle, since they came out of the vehicle"? That really puzzled me that the auto manufacturer would just throw in a few extra, just in case we happened to lose one in the process of changing our starter. Lately, I've come to think the human body is a lot like Grandpa's old Ford. I've recently talked to a friend, whose wife just had her appendix taken out. The doctor mentioned we really don't know what the appendix accomplishes, maybe some type of filter. Then yesterday, after meeting with a client, their daughter was going in to have her tonsils removed. We can function fine without them, and their not sure why we even have them. Last night, we were discussing the time when my oldest daughter will have to have her wisdom teeth pulled. Doctors and dentists agree, they cause more harm than good, so they should be removed. So why are we born with all these extra parts? Surely they have to have a function? Grandpa used to keep all his extras, just in case somebody needed a nut, a bolt, a wire, whatever ailed your car. He WAS the Dr. Frankenstein of the auto world. Just imagine the extra parts he would have had on hand if he were a surgeon!