what was the name of the policy that would allow settlers in the new territories to vote for or against slavery?

The Kansas

Explanation:

The Kansas–Nebraska Act of 1854 called for popular sovereignty, requiring that the decision about slavery be made by the territory's settlers (rather than outsiders) and decided by a popular vote.

a historian researching the immigration policies of the early 1900s would expect a source written today,rather than in 1910 to :

( a ) be more interested in objective data and statistics.

the french revolution was when many people were persecuted for disagreeing or making separate government