Mama, why do we have eyebrows?

We were sitting on the floor playing Lego's, and Blake walks up to me, and says:

Blake:  Mama, why do we have eyebrows?  Is it so we can go like this ( he started moving his eyebrows really fast up an down making an excited face and then a frowning face over and over again)

Me: HAHAHAHA Thats probably one reason (as tears come out of my eyes from laughing so hard)

Blake:  What are the other reasons? (acting all serious)

Me:  Well, I am not really sure... Maybe we should ask Daddy when he gets home (thinking Kyle would get a kick out of the question.)

Blake:  Can't you just BING it, I want to know now.

Me:  (SHOCKED)  Sure, go get me the ipad.


First of all... BING IT?  He actually knows what a search engine is?  I must use that phrase more then I thought HAHA, and second, I cant believe he is starting to ask questions that I don't know the answer to.  I wonder what he will come up with next!

FYI, the reason we have eyebrows:

As we evolved and lost most of the thick hair on our bodies, why did we keep that little bit over the eyes?
Scientists aren't entirely sure why we kept this hair, but they have a pretty good guess. We know that eyebrows help keep moisture out of our eyes when we sweat or walk around in the rain. The arch shape diverts the rain or sweat around to the sides of our face, keeping our eyes relatively dry. The most obvious advantage of this is that it lets us see clearly when we're sweating a lot or out in the rain. Without eyebrows, getting around in these conditions is a little more difficult. The shape of your brow itself diverts a certain amount of moisture, but eyebrows make a significant difference in your ability to see. Diverting the sweat away is also good because the salt in sweat irritates the eyes, making them sting a little.