Answer:
I just think everyone should be left in America, and no boards should be kept up. Scientifically no one is a 100% american, If you dated about everyone a thousand years back everyone traveld from another country, so technically If all immigrants had to go back to were they came from, no one would be left in Anerica(it would be deserted)
I literally asked my history teacher this today
idk if this is graded for ur homework, but I wouldnt trust me