Knowledge: The first common sport played was soccer as it was easy to play with many people. On the other hand, hair color black has the most on this world.

Conversation:
I have brown hair. It is very common in human beings.
In fact, it's second only to black hair in how common it is.
That's what I said, haha. I wish I had red hair. I think it looks really cool.
That's nice. Once again, brown hair is the second-most common color.
Hmm okay. Then what is the first common one?

Response: Oh, the first common hair color is black.