Answer:
C is the right answer. The annihilation of up to 90% of the Native American population due to illnesses such as smallpox necessitated the growth of the African slave trade.
Explanation:
Because natives lacked an immune system capable of combating diseases brought in from Europe, C is the right answer. Of course, this resulted in the introduction of a slave system, as Europeans transported many slaves from Africa.
A is incorrect because the growth in the number of Europeans was due to a variety of social and economic factors.
B is also incorrect because it is not based on historical evidence.
D is also incorrect because it had no effect on the Natives' life expectancy.
