2
If we were to break each of these categories down into their components, we would have quite a long list of qualities and characteristics that make humans appear to be different from each other. I say appear to be different, because most of what I have listed represents what we see or hear, not what is true of human biology and physiology.
And as we learned in Shakespeare's The Merchant of Venice, if you prick us, any of us, "do we not bleed"? Of course we do, and we bleed red blood no matter what the color of our skin, or the language we speak, the clothing we wear, the gods we worship, or our geographical home.