Answer: Because they had never developed immunities to the disease
<span>The Erie Canal allwed for the American Midwest to transport their good via waterway to the port in New York City and then out to the world for consumption via trade. The Erie Canal was the largest civic project the United States built up to that point in time and made settling the midwest much more economical.</span>
Mercantilism is an example of an economic system, so your answer is C! :D
In population was 667.3 million in 1978. Hope this helped
