4points why discrimination and racism cause problems in a multi-ethnic society.
: )

Racism and discrimination cripples the society in every possible way. Human interractions constitute a fundamental aspect of how society works. Imagine discrimination in hospitals, schools and court houses. People of certain ethnicity would not be able to take advantages of public services whenever government employees would come from other group. It would also be impossible to operate in the private sector. You would have to look for certain stores, pharmacies and use services only from people of your own enthicity since all others would not treat you with respect and would not provide the best possible services. Therefore, a multi ethnic society need tolerance and mutual respect in order to function. Hope you can make 4 points of that ;) 

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