Improve the lives of the poor, hope this helps.
Srry i'm soo late but the answer is A. President McKinley's desire for war.
Hope i Helped :)
The Columbian Exchange<span> greatly affected almost every </span>society<span> on earth, bringing destructive diseases that depopulated many cultures, and also circulating a wide variety of new crops and livestock that, in the long term, increased rather than diminished the </span>world<span> human population..</span>
