The common belief that European (Western) are white, Africans are black, Middle East (including the Indian sub-continent) are Brown and East Asian (commonly called Asians or Orient) are lemonade skinned [and also from their eyes] is wrong!
You cannot differentiate any ethnicity by their facial appearance. Take for instance Arabs, Middle East person or North Indians have similar features with most Europeans ( that leads to the popular theory of Aryan migration). Spanish and Latin Americans have similar features with Indians. Also try Polynesians and people of South East Asia. There would not be much difference. Again Koreans, Chinese and Japanese cannot be differentiated by many.
Blacks from Europe and America are not African. They are very much under European or Western society and culture. If they were to fgo and visit Africa will they share they belief, way of life? So, it would be wrong to call them African.
Cant really. Sometimes, its possible but not always.
You'd have to expose yourself to people of a certain ethnic for a long period time.
first post is right, although different ethnicities may have a variety of features
There's no set in stone way to tell each person apart by facial features.
But here are some simple ones:
Asians: many of them have uniquely almond shaped eyes
Black people: many have kinkier type 4 hair and fuller lips
white people: many have fair skin and elongated noses
But these are just in general...so don't take them too seriously
Black ethnic groups:
Ethiopians often have more pointed noses instead of flat noses
The rest I don't know because Africans migrate into different countries VERY often
White ethnic groups:
Some Mediterraneans have bigger noses and look more arab sometimes, they also have sharper features and darker eyebrows
Northern Europeans have softer features, less sharp
Western Europeans have bulbous noses and pink skin
Asian ethnic groups:
Koreans and Chinese look kinda similar, I can't tell them apart. They have flat features (face, nose etc)
Japanese have wider eyes and not quite as flat faces usually
Southern Asian countries like Myanmar, Thailand have more exotic features, they look quite different