Which civil war battle is described as the single bloodiest day in the war

Did the spanish settlers and missions have a positive effect on world history? why, what did they do that was positive? why was the treaty of paris (1763) good for the world/world history? did the plymouth colony have a positive effect on world history? why, what did they do that was positive?

Why is the end of the cold war tied to the american domestic economy during this time?

Which item in the list are methods a political party might influence public opinion