There was a potato famine that greatly affected the Irish, many of whom decided to try to start a new life in the United States. The U.S. had a lot of immigration during that time.
The third option is correct so make sure to mark me branliest.
In the late 7th century, the Native American population dropped drastically due to a <span>contagious disease.
</span><span> contagious </span>diseases can transmit from person to another easily.