Would you consider someone biracial if their appearance just looks like one race?

Depends are they cute an how are they on personality

I would consider the person as "biracial" if he or she does not look like what his race is supposed to be (e.g. different hair than what White people's hair is supposed to be), and especially if that person has a parent or ancestry of a different race.

No I would ask them what race are they and if they tell me than it's fine by me.

I don't label people.

Yes. I consider anyone biracial whose parents are of two different races.

Many people do that. Obama is bi racial and they called him black. Lincoln was also biracial and people called him white but both men have the same color mother and same color father.

I honestly can't think of a scenario in which I would be called on to say what race another person is. But if there were such a need, I would follow tbat person's lead and however they describe themselves is how I would answer too.

Yes.