How did the idea of nation states and nationalism influence desire for war during world wars?

The idea of nationalism was positive at first. the people of respective states were full of nationalistic feeling. later this created pride in oneself and hatred towards other nations. this leads to aggressive nationalism or negative feeling towards nation. therefore the result was desire for war.

Yes you are cute answer theories to explain the colonization of the new world the last great habitable landmass to be occupied by humans focus on the bering land bridge, or beringia, which emerge by siberia and alaska the last ice age.