WHY? is our attempt to answer all the questions every little kid asks. Have a question? Send it to why@mentalfloss.com.

Your eyebrows are more important than you think. These little curves of hair have many jobs. Scientists think that eyebrows are like little tents for your eyes. When water or sweat rolls down your forehead, the shape of your eyebrows pushes it to the side of your face or to the sides of your nose so that you can still see what's in front of you. 

Without your eyebrows, things could slide into your eyes and hurt them. But they have other uses too. Eyebrows also help us recognize people we know. Like your eyes, mouth, nose, and ears, your eyebrows are different from everyone else's. If you didn't have them, it would be hard for your friends and family to know that you are you.

Eyebrows are also important because they can show how you feel. The way you move your eyebrows helps people guess if you are happy, sad, or angry. Some people move their eyebrows more than others, but we all do it—even when we don't mean to. The next time you talk to someone, watch their eyebrows to see if you can tell how they are feeling. 

To read more about how hair grows on your body, visit KidsHealth.