Humans are the only species on Earth that has exposed lips. No animal shows interior skin on their mouth like we do.

Goosebumps are the result of flexing muscles at the base of each hair follicle. There are two reasons humans get goosebumps. The first happens when someone is cold. The second is when you're scared and works much like a cat's fur when it feel threatened - By raising the hair when we’re ready to fight it made us appear bigger. Okay, it would, if we had fur.

At some point in our ancestral history, our ears moved directionally. Like a horse’s, we could move them around to be able to hear things better. While that ability is mostly gone, we all still have the auriculares muscle which surrounds the outer ear.

Although wisdom teeth are now simply painful and frail, they once served a very important purpose. A long, long time ago, pre-humans were primarily herbivores, which meant they ate a lot of greens. Because green vegetation takes longer to digest, it needed to be chewed more, and wisdom teeth gave the extra surface area needed to grind the greens into pulp.

Although the appendix does seem to produce some good gut germs to help the digestive system, we don’t really need it and those that have it removed suffer no real consequences. It seems it is simply left over from a previous version of us.

No animal on Earth had breasts like a human does. It seems like they evolved after we started walking upright. They began to become rounder and bigger until they've started to look like the boobs of Today.

Hiccups are left over from old body parts we no longer needed. There was this thing called a glottis at the entry to the lungs that would close off to not allow water into the organ. While the glottis is no longer there, a small trace remains. This underdeveloped muscle sometimes contracts when sucking in air and this uncontrollable contraction is what we now call the hiccups.