Question: If people can live healthily without certain body parts (such as tonsils), why do humans have these parts in the first place if they are not needed for survival?

Max Jamilly answered on 15 Mar 2018:

Nice question! Just because we can survive without a body part, it doesn’t mean they aren’t useful. Your tonsils, for example, are pretty useful for fighting infections. But they can also become infected, sore and swollen themselves so they are often removed. Thanks to modern medicine, we can deal with most infections without the help of our tonsils so they aren’t totally necessary.

We aren’t totally sure about all the functions of the appendix but, again, people can survive without one. It could be left over from our early ancestors who had a function for it. As we evolved, the appendix may have lost its function but still hands around because it doesn’t do much harm (most of the time).