How did European diseases affect the people of the Western Hemisphere? Why was this different from the effects in Europe? (two paragraphs)

I'm pretty sure it's c. extremely gradual but not 100% sure though.

Answerhave flowing water either episodically or during only a portion of the year;

Answer is b)eutrophication occurs when excess nutrients are present in aquatic ecosystems, resulting in the increased production of plant life and the subsequent decrease in the oxygen levels of the watereutrophication occurs when there are excess nutrients in a body of water. this results in plants having more food and reproducing  more, sometimes leading to more aquatic animal life as well. ultimately, this can reduce the oxygen level in the ecosystem.