Approximately what percentage of the global population currently lives outside their country of birth ?

A. Racial and ethnic groups often have the potential for carving out their own independent nations from the existing state
B. Racial and ethnic stratification is harder to eliminate than are other forms of stratification
C. All other forms of stratification grow out of racial and ethnic stratification
D. All of the above

A. are groups identified on cultural grounds
B. are based solely on nationality
C. occupy a small territory
D. unlike racial groups are socially constructed