which of the following best describes the changes brought to world populations as a result of the european colonization of the americas?           a. the european population nearly doubled, the native american population dropped greatly, and millions of africans were sent to the americas as slaves.   b. the african population nearly doubled, the native american population dropped greatly, and millions of europeans were sent to the americas as slaves.   c. the native american population nearly doubled, the african population dropped greatly, and millions of europeans were sent to africa.   d. the african population nearly doubled, the european population dropped greatly, and millions of native americans were sent to europe as slaves.