Mimicry plays an important role in social interaction.Cues like sneezing, laughing, crying and yawning may be ways of creating strong social bonds within a group. If it were, we might have wings instead of wisdom teeth.

Cold weather slows down the draining process, causing a mucus backup that can leave you with snotty sleeves.

Swollen nasal membranes or condensation can also cause a stuffed schnozzle.

We know that hormone-fueled changes in the body are necessary to encourage growth and ready the body for reproduction. Hormones like testosterone actually influence the development of neurons in the brain, and the changes made to brain structure have many behavioral consequences.

Long ago, they served as a useful third set of meat-mashing molars.

But as our brains grew our jawbone structure changed, leaving us with expensively overcrowded mouths.

Most cells in our bodies sport hair-like organelles called cilia that help out with a variety of functions, from digestion to hearing.

In the nose, cilia help to drain mucus from the nasal cavity down to the throat.

All skin, without coloring, would appear creamy white. These four hues mix in different proportions to create the skin colors of all the peoples of Earth.

Lastly, sepia-toned melanin, created in response to ultraviolet rays, appears black in large amounts.

Just as watching someone yawn can induce the behavior in yourself, recent evidence suggests that laughter is a social cue for mimicry.

Hearing a laugh actually stimulates the brain region associated with facial movements.